Brake 


Catechism 


Twenty=-Foiwtti  Edition 


of  the 
Brake 
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ibrica- 
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THE 

Air  Brake  Catechism 

AND 

Instruction  Book 

On  the  Construction  and 
Operation  of 

THE  WESTINGHOUSE 

AND 

THE  NEW  YORK 
AIR    BRAKES 

With  a  List  of 

Examination  Questions  for  Enginemen 
and  Trainmen  l 


'••       <7 


Copyright  by  C.  B.   Conger,  Grand  Rapids,  Mich. 
1910. 


Twenty  Fourth  Edition 


PREFACE 

X-bl-d 

24th  Edition 

In  this  enlarged  edition  of  the  Air  Brake  Catechism 
considerable  new  matter  has  been  added  which  will  prove 
of  interest  not  only  to  those  who  are  learning  about  the 
operation  of  the  brake  equipment  from  their  own  observa- 
tion and  experience,  but  to  those  who  have  the  advantage 
of  an  instruction  car  with  a  regular  instructor.  This 
subject  of  self-instruction  in  all  its  details  is  so  large  that 
only  a  small  part  of  it  can  be  taken  up  in  this  little  book, 
but  the  principal  points  are  brought- to  notice. 

The  work  done  by  the  air  brake  operator  in  handling 
trains  is  becoming  more  skillful  every  year;  he  who 
wishes  to  keep  up  with  the  best  practice  must  continually 
try  to  improve  his  work.  This  can  only  be  done  by  learn- 
ing and  practicing  the  best  methods.  Bear  in  mind  that 
good  judgment  is  the  first  requisite  for  a  successful  air 
brakeman,  the  addition  of  knowledge  of  the  construction 
so  as  to  locate  defects  and  their  remedies,  and  correct 
methods  of  handling,  to  good  judgment,  will  make  a 
skillful  man  under  all  conditions. 

At  the  present  day  every  one  connected  with  the  work- 
ing of  the  air  brake  is  expected  to  pass  regular  examina- 
tions, and  these  examinations  are  getting  more  strict  each 
year.  The  list  of  examination  questions  will  call  atten- 
tion to  points  in  the  construction  and  handling  of  the 
brake  which  you  should  know  if  you  wish  to  pass. 

The  construction  and  operation  of  the  air  pump,  brake 
valve  and  triple  valve,  as  far  as  it  interests  enginemen,  is 
explained,  the  matter  of  repairs  is  not  taken  up. 

All  the  new  designs  of  locomotive  and  high  duty  car 
brakes  of  both  Air  Brake  companies  that  are  in  general 
service  at  this  date  are  explained  in  this  Catechism. 


INTRODUCTION 

At  the  present  day  so  much  depends  on  the  proper 
handling  of  the  Automatic  Brake  that  a  definite  knowledge 
is  required  from  all  men  in  train  service  of  its  operation 
when  in  good  order,  and  how  to  locate  defects  or  break- 
downs, as  well  as  how  to  avoid  the  difficulties  arising  from 
them. 

This  applies  to  the  veteran  as  well  as  to  the  beginner. 
The  changes  in  the  mechanism,  caused  by  the  new  and 
improved  devices  brought  into  service  to  take  care  of 
longer  freight  trains  and  faster  passenger  trains,  as  well 
as  the  devices  for  independent  operation  of  the  locomotive 
brake,  call  for  study  on  the  part  of  the  men  who  have 
handled  the  brake  for  years,  for  a  passenger  train  of 
moderate  length  equipped  with  ordinary  triple  valves 
and  a  long  train  with  all  high  speed  brakes  are  two* 
widely  different  propositions,  and  the  veteran  looks  for 
information  on  them.  As  for  the  beginner,  he  can  not 
learn  it  all  from  experience,  as  no  one  is  allowed  to* 
handle  important  trains  until  he  has  shown,  either  by  an 
examination  or  by  handling  a  moving  train  •  under  the 
supervision  of  some  man  who  can  judge,  that  he  has 
the  necessary  knowledge  to  properly  operate  the  brake 
under  all  ordinary  conditions. 

This  has  brought  about  a  demand  for  a  clear  and  prac- 
tical form  of  instruction  in  air  brake  practice,  not  so  much 
to  instruct  the  beginner  on  all  the  points  as  to  put  him  in 
the  way  of  learning  them  himself;  and  this  introductory 
chapter  is  intended  to  help  those  who  set  out  to  learn  the 
theory  and  have  a  chance  to  operate  the  brake  or  see  it 
operated.  This  can  best  be  done  by  learning  the  foun- 
dation principles  first,  studying  the  action  of  the  important 
primary  parts  of  the  machine;  the  secondary  parts  will 
then  work  their  way  in  so  you  understand  the  whole 
properly.  Much  time  may  be  wasted  by  beginning  at  the 

-in 


4  SELF    INSTRUCTION 

wrong  end  to  unravel  ?ir  brake  operations.  If  you  are 
too  hasty  and  jump  at  conclusions,  you  may  be  wrong; 
better  not  know  anything  about  it  than  know  it  wrong. 
Therefore,  take  time  enough  at  first  to  learn  it  right; 
you  will  never  regret  it. 

There  is  nothing  mysterious  about  the  operation  of  the 
air  brake.  Each  part  has  its  own  duty  to  perform.  Take 
each  part  by  itself  and  study  it  up,  then  get  an  idea  of  its 
relation  to  the  other  parts,  and  you  will  find  out  that  it  is 
easy.  You  cannot  learn  it  all  at  once,  or  by  once  reading 
over  an  instruction  book.  In  studying  the  construction 
and  principle  on  which  it  operates,  it  is  an  advantage  to 
have  help  from  some  one  who  can  instruct  you.  When 
you  come  to  operate  it,  the  machinery  in  actual  operation 
is  the  best  instructor. 

When  you  see  the  air  brake  working  every  day,  some- 
times making  a  good  stop,  at  others  not  controlling  the 
train  as  you  think  it  should,  the  operation  may  seem 
mysterious,  but  it  is  governed  by  fixed  laws  of  mechanics 
and  forces.  If  you  take  pains  to  learn  these  laws  and 
about  the  forces,  and  examine  each  part  of  the  mechanism, 
it  will  be  clear  to  you. 

Attention  is  called  to  explanations  of  some  of  these 
operations  in  the  succeeding  pages  of  the  Air  Brake  Cate- 
chism. Many  of  these  operations  are  explained  in  more 
than  one  manner  in  connection  with  the  movements  of 
other  parts  of  the  apparatus. 

In  the  first  place,  all  the  parts  of  the  brake  which  are 
named  in  question  1  of  the  Catechism,  are  charged  with 
compressed  air,  which  comes  from  the  air  pump  to  the 
main  reservoir,  then  through  the  ports  in  the  brake  valve 
into  the  brake  pipe  and  triple  valve,  from  there  it  passes 
through  the  feed  port  in  the  triple  valve  into  the  auxiliary 
reservoir  provided  for  each  complete  brake.  When  the 
brake  is  ready  to  operate,  the  pressure  is  equal  in  the 
brake  pipe,  in  the  triple  valve  on  both  sides  of  the  triple 
piston,  and  in  the  auxiliary  reservoir.  When  you  change 
the  relation  of  these  pressures  in  different  parts  of  the 


PLAIN     TRIPLE    VALVE  5 

equipment,  the  effort  the  compressed  air  makes  to  equalize, 
by  the  high  pressure  air  pushing  against  the  low  pressure 
air,  moves  the  different  parts  of  the  air  brake  that  can  be 
moved  in  this  manner  away  from  the  high  pressures. 

When  it  is  once  fixed  in  your  mind  what  pressure  you 
have  in  each  place,  and  that  any  change  of  pressure  will 
cause  the  movable  parts  of  the  valves  to  change  their 
positions,  closing  some  of  the  openings  through  which  the 
air  can  pass  and  opening  others,  it  is  plain  that  the  next 
step  is  to  find  out  just  what  openings  the  air  must  pass 
through  at  each  operation,  whether  applying  or  releasing 
the  brake,  always  remembering  that  the  high  pressure  air 
tries  to  flow  into  a  space  of  lower  pressure. 

When  studying  the  equalizing  processes  in  the  operation 
of  compressed  air  equipment,  remember  that  it  is  air  that 
flows  from  one  part  of  the  equipment  to  another  and  not 
pressure.  Pressure  is  only  a  condition,  air  is  a  substance 
or  material.  A  substance  can  flow  from  one  cavity  or 
receptacle  to  another,  but  a  condition  can  not  flow  through 
an  opening.  When  compressed  air  flows  from  any  part  of 
the  equipment  to  another,  as  from  the  auxiliary  to  the 
brake  cylinder,  it  will  change  the  conditions  or  pressure 
in  these  places,  but  the  pressure  does  not  flow  either  way. 

It  will  take  away  much  of  the  mystery  of  equalization 
if  you  will  bear  these  facts  in  mind. 

We  will  take  up  the  plain  triple  valve  first,  as  the 
process  of  equalization  is  best  explained  with  it.  You 
will  notice  in  the  cut  on  next  page  of  the  plain  triple  valve 
in  the  position  for  charging  the  auxiliary  reservoir  and 
exhausting  the  air  from  brake  cylinder,  that  the  triple 
piston  5  is  the  dividing  line  when  the  pressures  are 
unequal;  that  the  brake  pipe  pressure  is  against  the  lower 
side  of  this  piston  and  auxiliary  pressure  on  top.  There  is 
a  small  passage  cut  in  the  side  of  the  cylinder  around  the 
piston,  called  a  feed  port,  at  m,  through  which  air  can 
pass  from  the  brake  pipe  around  the  piston  5,  and  up 
beside  the  slide  valve  6  into  the  auxiliary  at  K,  when  triple 
piston  is  clear  up  in  release  position;  this  is  the  opening 


6 


PLAIN    TRIPLE    VALVE 


through  which  air  can  equalize  in  brake  pipe  and  auxiliary. 
The  piston  acts  as  a  valve  to  open  and  close  this  feed  port. 
This  port  m  is  very  small,  and  equalization  takes  place 
slowly  through  it.  A  brief  explanation  of  the  reasons  for 
its  small  size  is  found  farther  along  in  the  book. 

As   the   auxiliary   stores   the   compressed   air   used   for 
applying  its  own  brake,  it  must  first  be  charged  with  a  full 


2.  Triple-Valve  Body 

3.  Cylinder  Cap. 
Cap  Nut. 
Piston 

Slide  Valve. 
Graduating  Valve. 
Graduating  Stem. 
Graduating  Spring. 

10.  Graduating-Stem  Nut. 

11.  Cylinder  Gasket. 

12.  Packing  Ring. 
14.     Bolt  and  Nut. 

18.     Slide- Valve  Spring 


RELEASE    AND    EXHAUST    POSITION. 

supply  of  air;  which  will  raise  its  pressure  to  the  stand- 
ard— usually  70  pounds — and  it  takes  about  a  minute  and 
10  seconds  for  air  enough  to  flow  around  the  piston  to 
equalize  the  pressure  at  70  pounds.  To  apply  the  brake 
with  a  triple  valve  the  brake  pipe  pressure  must  be  re- 
duced. As  soon  as  any  reduction  of  pressure  is  made  in 
the  brake  pipe  the  auxiliary  pressure  will  be  greater  and 


SERVICE    APPLICATION  7 

force   the   triple    piston    down,    following   the    decrease    of 
pressure  in  brake  pipe   end   of  triple. 

This  first  movement  of  the  piston  does  not  set  the 
brake.  There  is  some  slack  between  the  collar  on  the 
piston  rod  and  the  top  of  slide  valve  6 — about  five  thirty- 
seconds  of  an  inch — a  very  slight  reduction  of  pressure 
under  the  piston  moves  it  down  the  amount  of  this  slack, 


SERVICE    APPLICATION. 


LAP   POSITION. 


closing  feed  port  m  and  pulling  graduating  valve  7  off  its 
seat  in  slide  valve.  As  the  slide  valve  has  the  auxiliary 
pressure  holding  it  on  its  seat,  more  change  of  pressure 
under  the  piston  is  needed  to  move  the  slide  valve — a 
point  to  remember  when  you  move  the  triple  valve  to 
release  position.  When  the  piston  comes  down,  bringing 
with  it  the  slide  valve,  a  port  £,  leading  from  the  seat 
of  graduating  valve  7,  is  opened  to  f,  allowing  the 


8  SERVICE    APPLICATION 

auxiliary  air  to  pass  from  the  graduating  valve  into  the 
brake  cylinder.  This  also  has  a  movable  piston  that 
pushes  against  levers  which  are  so  coupled  up  that  the 
brake  shoes  are  forced  against  the  wheels.  The  operation 
of  this  triple  piston  with  a  moderate  reduction  of  brake 
pipe  pressure,  say  from  70  pounds  down  to  63,  will  show 
the  exactness  of  this  equalization  principle. 

When  the  triple  piston  5  comes  down,  following  a 
reduction  of  7  pounds  in  the  brake  pipe  (and  the  piston 
does  not  wait  till  the  entire  reduction  of  7  pounds  is 
made),  and  slide  valve  6  and  graduating  valve  7  opens, 
the  air  in  the  auxiliary  at  70  pounds  begins  to  expand 
into  the  brake  cylinder,  as  shown  in  cut  of  service  appli- 
cation. As  soon  as  enough  air  has  gone  into  the  cylinder 
to  reduce  the  auxiliary  pressure  a  little  below  63  pounds, 
the  brake  pipe  pressure  is  then  greatest;  hence  triple 
piston  moves  up,  also  moving  the  graduating  valve  7 
and  closing  it.  This  cuts  off  the  flow  of  air  into  the 
brake  cylinder.  As  only  a  part  of  the  full  supply  of  air 
has  passed  into  the  brake  cylinder,  it  sets  the  brake  with 
a  partial  application  and  holds  it  set,  for  the  piston  does 
not  move  the  slide  valve  6  up  and  open  the  exhaust  port 
k  to  air  port  f,  as  shown  in  cut  of  release  position.  For 
a  more  detailed  statement  of  the  operation  of  the  graduat- 
ing valve,  see  the  answer  to  a  question  farther  along  in 
this  book.  Thus  you  see  the  triple  piston  moves  between 
the  brake  pipe  and  auxiliary  pressures,  always  towards 
the  lesser  one. 

A  graduating  stem  8  and  its  spring  9,  in  the  bottom 
case  of  the  triple,  serve  to  stop  the  piston  at  a  point  in  its 
travel  where  port  z  will  be  exactly  opposite  port  /.  This 
stem  and  -spring  are  not  moved  in  a  partial  service  appli- 
cation, because  when  these  ports  are  wide  open  the  air 
will  pass  from  the  auxiliary  to  the  cylinder  as  fast  as  it  is 
going  out  of  the  brake  pipe,  this  will  reduce  the  auxiliary 
pressure  as  fast  as  the  brake  pipe  pressure  reduces. 

If  the  relations  between  the  pressures  on  either  side  of 
triple  piston  are  changed,  it  will  move  toward  the  lower 


RELEASING     BRAKES 


pressure  until  the  limit  of  its  travel  is  reached,  or  until 
the  relation  between  the  pressures  is  changed  the  other 
way;  this  will  stop  its  movement  if  pressures  are  equal- 
ized, or  move  it  the  other  way  if  pressure  is  increased. 
Increasing  the  pressure  in  brake  pipe  side  of  triple  over 
the  auxiliary  moves  the  triple  piston  clear  up,  moves  the 
slide  valve  6,  opens  exhaust  port  k  to  air  port  f,  allows 


The  plain  triple  valve 
moves  to  this  position 
when  the  train  pipe  pres- 
sure is  lower  than  the 
equalizing  pressure  of  the 
cylinder  and  auxiliary 
either  with  a  quick  or  a 
slow  reduction. 


EMERGENCY    APPLICATION. 

the  air  to  escape  from  brake  cylinder  and  releases  the 
brake;  so  you  see,  charging  up  the  brake  pipe  to  standard 
pressure  releases  the  brake.  As  the  feed  port  m  is  also 
opened  when  the  piston  5  is  clear  up,  the  air  flows  into 
auxiliary,  equalizing  its  pressure  with  the  brake  pipe.  To 
change  the  relations  between  the  pressures  in  any  other 
way  is  done  by  letting  out  some  of  the  air — the  train  man 


10  EMERGENCY   APPLICATION 

releases  the  brake  by  bleeding  out  the  auxiliary  pressure 
until  it  is  lower  than  brake  pipe  pressure. 

If  a  reduction  of  the  brake  pipe  pressure  of  more  than 
20  pounds  is  made,  as  from  70  to  below  50,  the  auxiliary 
pressure  must  also  be  reduced  20  pounds  or  more  before  it 
will  allow  the  piston  5  to  move  up  and  close  the  graduating 
valve. 

The  brake  cylinder  is  of  such  a  size — if  it  has  the 
proper  piston  travel — in  proportion  to  the  auxiliary  reser- 
voir that  if  air  is  allowed  to  flow  from  the  auxiliary  into 
the  cylinder  it  will  equalize  in  both  of  them  at  about 
five-sevenths  of  the  original  pressure,  which  is  50  pounds 
in  case  of  70  pounds  originally.  After  this  equalization 
has  taken  place  no  more  reduction  of  pressure  will  be 
made  in  the  reservoir,  except  by  a  leak  or  at  the  bleeder 
and  the  triple  piston  will  move  clear  down  to  the  position, 
which  with  a  gradual  service  application  is  called  full 
application  position.  This  is  the  same  as  the  emergency 
application  position.  You  will  notice  the  slide  valve  has 
uncovered  the  air  port  f  so  air  can  pass  through  freely 
and  hold  the  brake  cylinder  pressure  equal  to  the  auxiliary 
pressure.  The  stud  or  post  on  the  bottom  of  triple  piston 
has  pushed  the  graduating  stem  8  down,  compressing  its 
spring  9.  This  spring  helps  to  stop  the  piston  5  at  the 
proper  place  with  a  partial  service  application  and  assists 
in  starting  the  piston  up  to  release  after  a  full  application. 

After  thoroughly  posting  yourself  on  the  way  in  which 
the  plain  triple  operates  by  the  reduction  or  equalization 
of  pressures,  you  can  then  take  up  the  engine  equipment. 
It  is  a  good  plan  to  know  just  how  the  pump  operates,  its 
care  and  management,  but  that  can  be  left  till  later;  it  is 
treated  of  farther  along  in  this  book.  The  pump  generally 
goes  ahead  with  its  work  from  beginning  to  end  of  the 
trip  without  much  attention  from  the  engineer;  the  rest 
of  the  equipment  depends  on  the  skill  and  knowledge  of 
the  engineer  for  its  successful  operation,  as  it  responds 
directly  to  his  manipulation. 

The  brake  valve  controls  the  passage  of  air  between  the 


THE   BRAKE   VALVE  11 

main  reservoir  and  brake  pipe  or  brake  pipe  and  the 
atmosphere. 

The  main  reservoir  air  pressure  is  always  in  the  top  of 
the  valve  holding  the  rotary  valve  13  on  its  seat;  the 
brake  pipe  air  is  under  the  equalizing  piston  17  at  all  times. 
The  air  over  the  piston  can  be  called  brake-valve  air. 
Brake  valve  and  brake  pipe  air  can  equalize  when  the 
rotary  is  on  running  position,  and  in  full  release.  This  is 
further  explained  in  detail  later  on.  The  equalizing 
piston  17  is  moved  up,  opening  the  discharge  or  brake 
pipe  exhaust  port  n,  or  down,  closing  the  port,  by  a  change 
of  pressure  on  either  side,  just  the  same  as  the  triple 
piston.  The  presures  are  changed  by  opening  or  closing 
the  various  ports  in  the  valve.  Opening  preliminary 
exhaust  port  h  reduces  the  pressure  over  piston  17  so  that 
brake  pipe  pressure  raises  the  piston;  brake  pipe  pressure 
reducing  through  port  n  brings  piston  down.  The  rotary 
13  is  moved  by  the  engineer,  its  office  is  to  put  in  com- 
munication the  various  openings  or  ports  that  will  let 
the  air  pass  through.  Locate  these  ports,  next  find  out 
just  what  they  are  for  and  in  what  positions  of  the  rotary 
they  are  open  and  shut.  The  best  way  to  do  this,  if  you 
have  no  sectional  valve  to  study  on,  is  to  get  a  complete 
valve  for  a  few  hours  and  dissect  it,  using  a  piece  of  fine 
copper  wire  to  run  through  the  ports,  which  will  show 
the  course  of  the  air;  this  wire  can  be  bent  in  any  direc- 
tion and  its  use  is  not  likely  to  scratch  the  seats  or  valve. 
After  locating  all  the  ports  through  which  main  reservoir 
air  can  flow  into  brake  pipe  or  the  chamber  D  over  piston 
17,  then  see  in  what  position  of  the  rotary  all  ports  are 
covered,  and  figure  out  which  ports  are  covered  first  and 
why  it  is  necessary  to  stop  the  flow  of  air  through  them. 

You  will  probably  notice  that  before  any  ports  are 
opened  to  allow  air  to  escape  from  the  brake  pipe  the  main 
reservoir  air  is  cut  off  from  the  brake  pipe,  so  it  can  not 
supply  the  brake  pipe  while  you  are  reducing  that.  Other- 
wise the  triple  valve  would  not  feel  any  reduction  of  pres- 
sure and  brake  would  not  be  set.  Then  when  you  come  to 


THE  BRAKE  VALVE  13 

locate  the  ports  that  are  opened  to  reduce  the  brake  pipe 
pressure  and  actuate  the  triple,  it  will  be  necessary  to 
know  just  exactly  the  principle  of  operation  of  the  equal- 
izing discharge  valve. 

On  a  long  train  the  reduction  of  brake  pipe  pressure 
must  be  the  same  at  each  triple  if  we  expect  each  brake 
to  be  set  at  the  same  time  and  with  the  same  relative 
power.  To  make  this  reduction  of  pressure  alike  for  all 
the  triples,  or  what  is  the  same,  for  all  the  cars  in  the 
train,  we  must  allow  the  air  to  escape  from  the  brake 
pipe  gradually  so  the  reduction  will  not  be  any  more 
violent  from  the  first  car  than  from  the  last  one,  nor 
should  the  escape  of  air  be  closed  till  the  same  reduction 
has  been  made  in  each  car.  The  discharge  should  not  be 
stopped  suddenly  before  the  pressure  in  the  last  cars  has 
equalized  with  the  first  ones,  or  the  momentum  of  air 
flowing  from  rear  cars,  as  well  as  equalizing  pressures  in 
all  cars,  will  raise  the  brake  pipe  pressure,  in  the  cars 
nearest  the  brake  valve  and  tend  to  release  their  brakes. 
This  gradual  closing  of  the  brake  pipe  exhaust,  the  brake 
valve  is  intended  to  do  automatically.  Its  principle  of 
operation  is,  the  engineer  makes  the  proper  reduction  of 
pressure  in  the  brake  valve  over  the  equalizing  piston  17. 
and  the  action  of  the  piston  17  reduces  the  brake  pipe 
pressure  to  an  equal  amount  in  all  the  cars,  whether  few 
or  many. 

Before  you  move  the  rotary  far  enough  to  open  the 
preliminary  exhaust  port  hf  the  equalizing  port  g,  which 
allows  brake  pipe  air  to  pass  from  brake  pipe  to  chamber 
D,  over  piston  17,  is  closed;  this  cuts  off  chamber  D  from 
any  other  pressure;  you  can  then  make  a  reduction  on  top 
of  piston  77,  so  brake  pipe  pressure  will  raise  it  up  and 
hold  discharge  n  open  till  the  pressure  below  is  a  little 
less  than  it  is  above,  when  piston  is  moved  down  by  the 
chamber  D  pressure,  closing  brake  pipe  discharge. 

With  the  equalizing  discharge  valve,  the  black  hand 
of  the  double  gage  is  connected  with  chamber  D  at  all 
times;  if  the  rotary  is  in  either  full  release  or  running 


14  THE   BRAKE   VALVE 

position  the  equalizing  port  g  connects  it  to  the  brake  pipe 
air  so  it  shows  that  pressure  also.  When  the  brake  is  set 
with  a  service  application,  the  pressures  equalize  so  nearly 
on  each  side  of  piston  at  the  instant  brake  pipe  exhaust 
closes  that  the  black  hand  is  expected  to  show  brake  pipe 
pressure  then  also.  In  the  emergency  position  the  black 
hand  does  not  at  once  show  the  amount  of  the  reduction. 
You  will  find  this  further  explained  later. 

If  the  packing  ring  in  piston  17  leaks  very  much,  the 
black  hand  will  show  brake  pipe  pressure  when  rotary  is 
on  lap,  as  the  air  pressures  can  equalize  past  this  leaky 
packing  ring;  all  of  them  leak  a  little.  There  is  a  leather 
gasket  above  this  piston  to  prevent  leakage  during  a  serv- 
ice application,  but  not  when  the  piston  is  in  normal 
position.  Look  out  for  this  defect  when  operating  the 
brake.  The  brake  valve  reservoir  is  connected  with  the 
valve  for  the  purpose  of  giving  a  larger  volume  of  air  to 
chamber  D  in  order  to  insure  a  gradual  reduction  of 
pressure  there. 

Up  to  this  point  we  will  assume  that  the  student  has 
followed  the  action  of  the  brake  in  a  service  or  graduated 
application.  There  is  what  we  call  the  emergency  or  quick 
action,  produced  by  a  different  set  of  operations  peculiar 
to  the  quick  action  triple  valve  only.  We  will  go  to  the 
beginning  and  inquire  why  this  action  is  necessary. 

On  a  long  train  of  air  braked  cars,  to  avoid  a  severe 
shock  to  the  rear  part  of  train  when  brakes  are  applied 
from  the  head  end  of  train  very  suddenly,  as  by  bursting 
a  hose  or  breaking  apart  of  the  train,  or  in  case  of  danger 
when  it  is  necessary  to  set  the  brake  from  the  engine  very 
hard  so  as  to  stop  as  quickly  as  possible,  the  brakes  should 
set  on  the  rear  cars  quicky  enough  so  the  slack  will  not 
run  up  against  head  cars  and  damage  cars  or  draft  gear. 
Then,  in  case  of  danger,  every  second  after  the  brake  is 
applied  at  the  engine  before  it  begins  to  set  on  last  cars 
and  hold  them,  the  train  is  getting  nearer  the  danger ;  so 
a  brake  that  can  be  set  instantly  on  the  whole  train  will 
stop  the  train  quicker  than  one  which  sets  slowly  from  car 


THE    TRIPLE    VALVE 


15- 


to  car.  With  the  plain  triples  the  air  in  brake  pipe  will  be 
exhausted  at  one  place  only,  either  where  an  opening  is 
made  in  brake  pipe  or  at  brake  valve;  this  takes  several 
seconds  to  affect  the  farthest  car.  If  an  opening  can  be 
made  to  exhaust  this  air  at  each  car  and  reduce  the  brake 
pipe  pressure,  the  action  of  the  brakes  on  a  long  train  can 
be  made  nearly  simultaneous,  so  nearly  so  that  the  brakes 
are  all  set  before  the  slack  can  run  out.  The  quick  action 


DETAILS. 

Triple  valve  body. 
3  Slide  valve. 
Piston. 

6  Slide-valve  spring. 

7  Graduating  valve. 


8  Emergency-valve  piston. 

9  Emergency-valve  seat. 

10  Emergency  valve. 

11  Rubber  seat. 

12  Check-valve  spring. 

13  Check-valve  case. 
15  Check  valve. 

21  Graduating  stem. 

22  Graduating  spring. 

QUICK -ACTION  TRIPLE  VAI/VE — RELEASE  POSITION. 

triple  is  designed  to  exhaust  a  portion  of  the  brake  pipe  air 


16  QUICK    ACTION    TRIPLE   VALVE 

at  each  triple,  so  as  to  set  the  next  brake  suddenly.  To 
thoroughly  understand  how  the  quick  action  triple  can 
exhaust  some  of  the  air  from  the  brake  pipe  suddenly  and 
reduce  the  pressure  so  as  to  affect  the  next  triple  in  the 
same  manner,  it  will  be  necessary  to  study  the  construction 
of  the  quick  action  valve.  This  triple  has  the  same  open- 
ings to  admit  air  from  the  brake  pipe  to  the  auxiliary  that 
we  find  in  the  plain  triple.  In  the  quick  action  triple  they 
are  shown  at  e  through  g  and  feed  port  *.  But  there  is 
another  channel  for  air  to  pass  from  the  brake  pipe  into 
the  brake  cylinder  in  this  valve,  which  is  from  the  check 
valve  case  13  into  y,  then  into  x  and  into  brake  cylinder  at 
£.  These  openings  are  ordinarily  kept  closed  to  the  pass- 
age of  the  air  in  either  direction;  the  rubber  seated  emer- 
gency valve  10  keeps  the  brake  pipe  air  from  getting  into 
the  cylinder,  and  the  check  valve  15  keeps  the  air  in  brake 
cylinder  from  getting  back  into  brake  pipe.  These  two 
valves  are  held  on  their  seats  by  a  spring,  shown  at  12,  as 
well  as  by  the  air  pressures.  Now  it  follows  that,  if  you 
wish  this  triple  to  make  an  opening  to  let  the  air  out  of 
"brake  pipe  suddenly,  this  valve  10  must  be  moved  away 
from  its  seat  against  the  brake  pipe  pressure  and  the  strain 
of  the  spring  12.  For  this  purpose  piston  8  is  used.  A 
port  t,  which  is  shown  just  over  the  figure  8,  can  be 
opened  by  the  slide  valve  j,  letting  the  air  from  the  auxil- 
iary on  top  of  piston  8\  with  auxiliary  reservoir  pressure 
over  this  piston  and  no  pressure  at  all  or  a  very  low  one 
l>elow  it,  piston  8  goes  down  instantly,  forcing  valve  JO 
away  from  its  seat.  The  brake  pipe  air  then  moves  check 
15  up  and  flows  through  C  into  brake  cylinder  till  press- 
ures equalize. 

When  these  valves  JO  and  15  are  opened  in  this  manner, 
the  brake  pipe  air  goes  past  them  like  a  flash  through  the 
large  ports  into  the  empty  brake  cylinder,  setting  the 
1)rake  with  the  pressure  at  which  the  brake  pipe  and  brake 
cylinder  can  equalize,  which  is  somewhere  near  20  pounds. 
At  the  same  time  port  s,  in  the  end  of  slide  valve  j,  is 
open,  air  from  auxiliary  flows  through  r  and  piles  in  on 


QUICK    ACTION    TRIPLE    VALVE  17 

top  of  brake  pipe  air  in  cylinder,  raising  the  cylinder  press- 
ure at  full  equalization  to  60  pounds.  The  brake  pipe  air 
equalizes  first  with  cylinder,  through  large  ports,  and 
auxiliary  pressure  last,  through  small  ports.  Considerable 
air  passes  around  piston  8,  which  is  not  an  air  tight  fit 
in  its  bushing. 

Now  for  the  means  employed  to  let  auxiliary  reservoir 
pressure  on  top  of  piston  8  at  one  time  to  produce  "quick 
action"  and  keep  it  out  at  another  to  preserve  the  grad- 
uated application.  As  long  as  this  triple  is  used  with  a 
graduated  application,  slide  valve  3  does  not  move -over 
far  enough  to  uncover  emergency  port  t,  as  with  a  gradual 
reduction  of  brake  pipe  pressure  auxiliary  presure  will 
be  reduced  equally  with  brake  pipe  pressure  through  the 
graduating  valve  7  and  its  port  s.  The  graduating  stem 
21  and  its  spring  22  ordinarily  stop  the  movement  of  the 
piston  4  when  it  reaches  the  service  application  position. 
But  if  brake  pipe  pressure  is  reduced  so  suddenly  and  to 
such  an  amount  that  the  graduating  valve  can  not  reduce 
auxiliary  pressure  equally  with  brake  pipe  reduction,  and 
graduating  spring  does  not  stop  the  piston,  the  greater 
auxiliary  pressure  will  move  piston  4  and  slide  valve  J 
far  enough  so  port  t  will  be  uncovered,  auxiliary  air  will 
move  piston  8,  valves  10  and  15  will  move  at  once  and 
"quick  action"  is  the  result.  The  Westinghouse  Co.  have 
made  a  quick  service  triple  valve  that  allows  a  small 
quantity  of  brake  pipe  air  to  flow  into  the  brake  cylinder 
during  a  service  application  and  another  type  that  uses- 
air  from  a  supplementary  reservoir.  These  will  be  de- 
scribed later  on  in  this  book. 

A  sticky  triple  valve  or  any  defect  in  valve  /  that  will 
prevent  air  getting  past  it  will  cause  quick  action  opera- 
tion with  a  moderate  service  application  if  you  have  a 
short  train.  The  equalization  of  pressures  is  the  founda- 
tion principle  to  look  for  in  the  operation  of  the  quick 
action  triple. 

It  is  necessary  to  restrict  the  flow  of  air  through  some 
of  the  openings  in  triples  and  brake  valve  in  order  to  be 


18  EQUALIZATION 

sure  to  handle  a  long  train  with  safety.  This  refers  more 
particularly  to  the  "feed  ports"  in  the  triples  for  recharg- 
ing auxiliaries,  the  "preliminary  exhaust  port"  h,  train 
pipe  exhaust  n  and  exhaust  ports  in  triple  valves.  The 
proper  size  of  these  ports  has  been  determined  by  the 
experience  of  many  years. 

Perhaps  it  would  be  well  to  study  on  the  matter  of 
equalization  of  different  pressures  of  air  in  the  equipment, 
as  if  this  is  well  understood  you  can  solve  other  problems 
in  air  brake  operations  more  easily.  It  is  the  law  that 
where  compressed  air  in  a  certain  sized  vessel  expands  into 
an  empty  one,  the  pressure  is  reduced  in  the  full  one  in 
proportion  to  the  increased  volume  the  air  has  to  occupy. 
From  this  you  can  see  that  in  the  case  of  the  brake  cylin- 
der and  auxiliary  the  auxiliary  pressure  will  be  reduced 
more  if  the  brake  cylinder  is  large  in  proportion  to  the 
auxiliary  than  if  it  is  small.  Apply  this  law  to  the  cylin- 
ders having  different  piston  travels;  a  cylinder  having  a 
long  piston  travel  holds  a  greater  volume  of  air  than  the 
one  with  short  travel,  so  we  can  expect  the  one  with  long 
travel  to  reduce  the  auxiliary  pressure  to  a  lower  point 
than  the  short  travel,  and  it  is  found  that  a  travel  of  11 
inches  of  the  freight  brake  piston  gives  a  final  equalized 
pressure  of  close  to  45  pounds,  while  a  short  travel  of  8 
inches,  which  is  between  4  and  11  inches,  will  give  a  final 
equalization  of  about  50  pounds.  The  difference  of  press- 
ures with  long  and  short  piston  travels  is  more  marked 
with  partial  applications  than  with  full  equalization  .  A 
5  pound  reduction  of  auxiliary  pressure  will  give  about  18 
pounds  per  inch  on  a  piston  with  4  inches  travel;  while 
with  the  11-inch  travel  piston,  the  pressure  will  not  show 
anything.  This  will  give  different  brake  powers  on  dif- 
ferent cars  in  the  train,  although  it  should  be  equally 
proportioned  to  the  weights  of  the  cars;  unequal  brake 
power  makes  some  cars  hold  less  than  others,  so  the  strain 
is  not  equally  distributed  throughout  the  train,  a  point 
in  equalization  worth  studying  on. 

The  final  point  at  which  auxiliaries  and  their  cylinders 


EQUALIZATION  19 

equalize  cuts  quite  a  figure  in  operating  the  triples  to 
release  the  brakes.  A  variation  in  piston  travel  of  the 
different  brakes  changes  this  point  of  final  equalization 
and  will  be  explained  later.  As  was  stated  in  explaining 
the  operation  of  the  triple  piston,  the  brake  pipe  pressure 
must  be  greater  than  the  auxiliary  pressure  to  move  the 
triple  piston  up  so  slide  valve  will  open  exhaust  port  and 
let  air  in  brake  cylinder  equalize  with  the  atmosphere; 
then  the  brake  piston  will  have  no  air  pressure  on  either 
'side  of  it.  This  relieves  -the  strain  on  brake  levers  and 
shoes. 

If  auxiliary  pressures  on  this  final  equalization  are 
unequal  and  brake  pipe  pressure  is  not  raised  at  once 
higher  than  the  highest  auxiliary  pressure,  all  the  brakes 
will  not  release  at  once.  This  leads  us  to  consider  the 
question  of  equalization  of  the  train  pipe  and  main  reser- 
voir pressures  when  you  desire  to  release  the  brakes. 

If  the  brake  pipe  is  long  it  will  take  more  air  from  main 
reservoir  to  equalize  at  a  certain  stated  pressure  than  if  it 
is  short,  for  a  long  brake  pipe  holds  more  air  than  a  short 
one.  Then,  again,  if  the  brake  pipe  has  considerable  com- 
pressed air  left  in  it  after  setting  the  brake,  it  will  equalize 
at  a  higher  point  than  if  it  is  empty.  This  emphasizes  the 
fact  that  it  will  be  hard  work  to  release  the  brakes  on  a 
long  train  if  you  exhaust  all  the  air  in  making  an  ap- 
plication. 

Another  place  where  equalization  is  important  is  on  the 
second  application  shortly  after  releasing  brakes.  It  takes 
time  for  the  brake  pipe  and  auxiliary  pressures  to  equalize. 
If  you  do  not  wait  this  proper  time  the  auxiliary  will  not 
have  charged  to  standard  pressure,  and,  of  course,  when 
brake  is  set  it  will  not  reach  as  high  a  final  pressure  on 
brake  piston,  which  reduces  the  braking  power. 

Equalization  between  brake  pipe  and  auxiliary  on 
making  the  reduction  for  a  second  application  is  very 
important,  because  if  brake  pipe  has  a  high  pressure  which 
the  auxiliary  has  not  reached,  the  triple  piston  cannot 
move  till  the  brake  pipe  pressure  has  been  drawn  down  a 


20  BRAKE  OPERATION 

trifle  lower  than  the  auxiliary.  If  one  is  80  and  the  other 
60,  it  means  a  reduction  of  20  pounds  before  brake  begins 
to  set,  and  about  20  more  to  set  all  brakes  tight.  This 
affects  the  work  of  the  brake  on  a  short  train  more  than 
a  long  one.  With  a  large  main  reservoir  and  a  short  train 
it  is  easily  done. 

This  defective  handling  of  the  brake  is  called  "over- 
charging the  brake  pipe,"  and  can  be  avoided  by  returning 
the  brake  valve  to  lap  from  full  release  as  soon  as  the 
brake  pipe  has  had  time  to  charge  up  its  whole  length, 
which  will  move  all  triples  to  exhaust  position  and  quickly 
equalize  the  brake  pipe  and  auxiliary  pressures.  When 
these  pressures  are  equalized,  a  very  slight  reduction  in 
the  brake  pipe  pressure  sets  all  the  triples  to  work  at  once. 
In  stopping  a  short  passenger  train  for  baggage  or  at  a 
water  plug,  if  the  stop  is  being  made  too  soon,  go  to  a  full 
release  for  an  instant  to  move  all  the  triples  to  release, 
then  back  to  service  application,  making  a  service  reduc- 
tion of  6  or  8  pounds  which  will  probably  set  the  triples 
before  all  the  air  has  passed  out  of  brake  cylinders,  and 
in  addition  to  holding  the  brake  set  at  a  low  pressure  will 
have  all  of  them  ready  for  a  further  application  at  an 
instant's  notice  so  that  you  can  stop  at  the  exact  spot 
required.  Never  try  this  with  a  long  train  of  any  kind  at 
slow  speed,  as  you  are  liable  to  break  the  train  in  two. 

A  few  hints  on  getting  ready  to  make  a  good  stop  and 
knowing  whether  you  can  depend  on  the  brake  to  operate 
properly  may  be  of  service  here. 

When  operating  the  brake  valve,  you  should  listen  to 
the  sound  of  the  brake  pipe  air  discharging  from  it, 
because  the  sound  tells  how  many  cars  you  have  in  your 
train  with  brake  pipe  connected  and  how  the  valve  is 
doing  its  work,  just  as  the  exhaust  of  the  locomotive  tells 
whether  the  valve  motion  is  in  order;  any  unusual  sound 
notifies  you  that  something  is  wrong. 

When  you  make  a  test  of  the  train  brake  before  start- 
ing out,  make  the  same  kind  of  an  application  as  when 
stopping  at  a  station,  by  successive  reductions;  a  5  to  7 


BRAKE     OPERATION  21 

pound  reduction  for  the  first  one,  lighter  ones  afterwards; 
then  you  will  know  how  the  brake  will  work  when  making 
station  stops.  It  should  be  full  application  to  get  the  full 
piston  travel. 

Never  make  an  emergency  application  when  testing 
brakes  unless  specially  called  for,  and  then  not  till  after 
the  first  test  has  been  finished. 

If  the  brake  leverage  on  the  train  is  adjusted  for  70 
pounds  train  pressure,  it  is  not  safe  to  carry  either  more  or 
less.  If  you  carry  less,  you  cannot  stop  quickly  when  you 
have  to;  if  you  carry  more  and  skid  the  wheels,  you  will 
slide  by  and  will  spoil  a  lot  of  wheels.  We  will  speak  of 
this  matter  of  leverage  later  on  in  connection  with  the 
High  Speed  Brake  and  L  Triple. 

Have  your  air  gage  properly  placed  and  well  lighted, 
so  that  it  can  be  seen  without  taking  your  eyes  too  far  off 
the  track  and  signals.  Consult  it  often  till  you  learn  the 
air  brake  business.  If  it  does  not  register  correctly  or 
sticks  when  the  pressure  is  changing,  call  the  attention  of 
the  proper  party  to  it. 

It  pays  to  inspect  and  test  your  engine  equipment  care- 
fully before  leaving  the  engine  house;  it  may  save  you  a 
failure  on  the  road. 

Drain  the  main  reservoir  daily;  the  distributing  valve 
and  the  tender  triple  should  be  drained  regularly  in  cold 
weather.  It  is  a  good  plan  to  open  the  cocks  at  rear  of 
tender  and  blow  out  the  train  pipes  for  both  brake  and 
signal  line  before  coupling  to  the  train. 

Too  much  .oil  used  in  the  air  end  of  the  pump  does 
more  harm  than  not  enough,  as  it  chokes  up  all  the  small 
openings  in  the  engine  equipment.  The  piston  rod  pack- 
ing needs  more  oil  than  the  air  piston;  the  air  valves  do 
not  need  any.  Use  good  valve  oil  always. 


WHEN   OPERATING  THE   AUTOMATIC   BRAKE 
REMEMBER 

That  the  compressed  air  stored  in  the  main  reservoir  is 


22  BRAKE    OPERATIONS 

used  to  charge  up  the  brake  pipe  and  auxiliary  reservoirs, 
and  that  it  is  used  to  release  the  brake.  Do  not  have  any 
water  in  any  reservoir,  as  it  takes  up  the  room  needed 
for  air. 

That  the  compressed  air  stored  in  auxiliary  reservoir 
is  used  to  set  the  brake.  There  is  an  independent  supply 
for  each  brake.  Keep  a  full  supply  in  each  auxiliary. 

That  the  brake  is  set  by  any  reduction  of  pressure  in 
the  brake  pipe,  no  matter  how  it  is  made,  if  it  is  sufficient 
to  move  the  triple  piston  and  valve. 

That  the  brake  pipe  pressure  must  be  reduced  5  to  7 
pounds  at  first  application,  or  brake  pistons  will  not  travel 
over  leakage  grooves,  allowing  brake  to  leak  off. 

That  the  brake  pipe  pressure  must  be  raised  above  the 
auxiliary  pressure,  or  the  auxiliary  pressure  reduced  by 
bleeding,  before  the  brake  will  release. 

That  you  cannot  recharge  an  auxiliary  reservoir  until 
the  exhaust  port  in  triple  is  wide  open,  unless  air  leaks 
past  triple  piston,  as  the  feed  port  does  not  open  until 
after  the  exhaust  port  is  open. 

That  a  second  application  after  release  does  not  set  the 
brake  as  tight  as  the  first  full  application,  unless  the 
auxiliaries  have  had  time  to  recharge  to  standard  pressure. 
This  takes  from  25  to  45  seconds. 

That  the  small  reservoir  attached  to  brake  valve  is  put 
there  to  give  a  larger  supply  of  air  for  the  preliminary 
exhaust  of  brake  valve  so  you  can  make  a  gradual  re- 
duction. 

That  if  your  driver  brake  does  not  work  quickly  and 
hold  well  with  service  application,  in  ninety-nine  times  out 
of  a  hundred  it  is  on  account  of  a  leak. 

That  the  distributing  valve  used  with  the  locomotive 
brake  must  be  kept  clean  and  all  pipe  joints  tight  if  you 
expect  to  get  good  service  from  it. 

That  the  position  of  the  straight  air  brake  valve  and 
the  independent  brake  valve  has  all  to  do  with  the  applica- 
tion and  release  by  the  automatic  brake  valve  of  the 
locomotive  brake. 


DEFINITIONS  23 

That  in  all  these  questions  and  answers  it  is  under- 
stood unless  otherwise  stated,  that  70  pounds  is  the  stand- 
ard brake  pipe  and  auxiliary  pressure;  90  pounds  main 
reservoir  pressure;  and  8  inches  the  standard  piston  travel 
for  all  passenger,  freight  and  tender  brake  pistons.  The 
brake  piston  travels  an  inch  or  more  farther  when  train  is 
running  than  with  a  standing  test,  so  travel  should  be 
adjusted  to  less  than  8  inches. 

And  lastly,  we  will  define  some  of  the  terms  which  are 
used  to  shorten  the  explanations  you  may  hear. 

A  PARTIAL  application  means  that  the  brake  is  set  with 
part  of  its  full  force ;  the  brake  cylinder  pressure  has  not 
equalized  with  the  auxiliary  reservoir  pressure. 

A  FULL  application  means  that  the  brake  cylinder  press- 
ure has  equalized  with  the  auxiliary  pressure,  and  has, 
therefore,  got  the  full  pressure  that  can  be  obtained  from 
the  air  stored  in  the  auxiliary.  Be  sure  to  distinguish 
between  a  reduction  and  an  application  when  telling  any 
one  how  the  brake  worked.  A  reduction  is  allowing  air 
to  pass  out  of  the  train  pipe  whether  the  brake  sets  full 
or  partially.  No  matter  how  many  reductions  of  brake 
pipe  pressure  you  make,  it  is  only  one  application  till  it  is 
released.  You  can  reduce  the  brake  pipe  pressure  a  few 
pounds  at  a  time  and  make  eight  or  ten  successive  reduc- 
tions, but  it  is  only  one  application  if  it  has  not  been 
released. 

A  GRADUATED  OR  SERVICE  application  means  a  gradual 
reduction  of  brake  pipe  pressure  which  sets  the  brake 
slowly.  In  a  graduated  application  it  is  not  expected  that 
the  quick  action  parts  of  any  triple  valve  will  operate. 

An  EMERGENCY  application  means  a  sudden  and  heavy 
enough  reduction  of  brake  pipe  pressure  to  set  the  brake 
with  full  force  at  the  first  movement  of  the  triple  valve. 
With  this  application  the  quick  action  part  of  the  triple 
valve  operates,  so  that  air  from  the  brake  pipe  passes  into 
the  brake  cylinder  and  equalizes,  after  which  the  auxiliary 
and  cylinder  pressures  also  equalize. 


THE  8  INCH   AIR    PUMP 

The  sectional  view  of  this  pump  shows  the  steam  and 
air  pistons  10  and  11  and  all  the  steam  valves  in  their 
positions  when  the  steam  piston  is  making  its  stroke 
upward. 

The  live  steam  comes  from  the  boiler  through  the 
governor  and  passage  m  into  the  chamber  between  the 
heads  of  the  main  steam  valve  /.  It  also  goes  into  port  h 
and  through  a  passage  in  the  wall  of  the  steam  cylinder 
and  in  the  top  head,  which  is  not  shown  as  this  port  is 
in  the  section  cut  away.  This  passage  from  h  leads  live 
steam  constantly  into  the  steam  chest  e  of  the  reversing 
valve  16;  it  can  pass  through  port  a  into  the  cylinder 
and  over  the  reversing  piston  23,  pushing  it  down;  for 
the  combined  area  of  the  piston  23  and  the  small  one  7 
is  greater  that  that  of  the  top  one  7.  This  opens  the 
steam  port  in  the  bushing  26]  steam  then  passes  under 
steam  piston  10. 

At  the  same  time  the  exhaust  ports  in  bushing  25  are 
open  so  any  steam  in  the  top  end  of  the  cylinder  escapes 
at  y  through  /  and  g  to  the  exhaust  pipe.  This  moves  the 
steam  piston  up,  bringing  up  the  air  piston  n.  As  the  air 
piston  moves  up,  any  air  above  it  escapes  through  port  p 
by  raising  discharge  valve  30  and  passes  into  the  main 
reservoir.  At  the  same  time  the  lower  end  of  the  air 
cylinder  is  filled  with  air  from  the  atmosphere;  when  the 
piston  ii  raises,  a  partial  vacuum  is  formed  under  it  and 
the  pressure  of  the  outside  air  forces  up  inlet  valve  33  and 
air  passes  into  cylinder.  On  the  arrival  of  the  piston  at 
the  top  of  its  stroke,  both  these  air  valves,  30  and  33,  drop 
into  their  seats,  remaining  there  during  the  return  or 
down  stroke.  The  other  set  of  air  valves  open  on  the 
down  stroke,  31  to  admit  air  above  the  piston  32  to  dis- 
charge air  from  the  lower  end  of  the  air  cylinder  to  the 
main  reservoir. 


26  THE     AIR     PUMP 

When  the  steam  piston  reaches  the  top  of  its  stroke, 
the  reversing  plate  18  strikes  the  shoulder  n  of  the  revers- 
ing rod  17,  moving  it  up;  this  in  turn  moves  the  reversing 
valve  16  up  also.  Reversing  valve  16  being  moved  up  in 
chamber  e  covers  port  a  so  live  steam  can  no  longer  pass 
on  top  of  reversing  piston  23 ;  ports  b  and  c  are  connected 
by  the  cavity  in  valve  16  so  that  the  steam  in  cavity  d  over 
piston  23  exhausts  through  c  and  balances  the  pressure 
on  each  side  of  piston  23.  The  top  piston  of  main  steam 
valve  7,  which  has  live  steam  under  it,  being  larger  than 
the  bottom  one  and  piston  23  being  balanced,  the  main 
steam  valve  7  is  raised  up,  also  moving  up  23-,  this  move- 
ment of  7  opens  the  upper  steam  ports  and  the  lower 
exhaust  ports  so  that  live  steam  pushes  the  piston  10 
down  to  the  bottom  of  the  cylinder.  When  the  piston 
reaches  the  bottom  of  the  stroke,  the  reversing  plate  18 
catches  on  the  button  x  at  the  bottom  end  of  reversing 
rod  17  and  moves  the  reversing  valve  back  to  the  position 
shown  in  the  cut;  the  live  steam  then  moves  the  piston 
valves  23  and  7  to  the  positions  shown  there,  and  the 
pump  is  ready  for  the  up  stroke. 

The  first  sectional  view  of  the  9^-inch  pump  is  shown 
with  the  main  piston  65  and  all  the  valves  in  the  steam 
end  as  they  stand  when  the  pump  is  making  the  upward 
stroke.  The  live  steam  which  comes  up  through  passage 
a  at  the  back  of  the  pump  into  steam  chest  A  is  always  on 
top  of  the  main  slide  valve  83.  This  valve  is  shown  at  the 
right  hand  end  of  its  stroke,  in  which  position  it  uncovers 
port  b  so  steam  can  pass  down  to  the  bottom  end  of  steam 
cylinder  under  the  piston  65  and  push  it  upward.  At  the 
same  time  the  exhaust  cavity  of  this  slide  valve  83  con- 
nects the  port  c,  which  opens  into  the  top  end  of  the  steam 
cylinder,  with  exhaust  port  d,  which  passes  down  around 
the  back  of  cylinder  to  the  exhaust  pipe;  the  steam  above 
the  piston  can  then  pass  into  the  exhaust.  This  slide  valve 
83  is  moved  by  the  differential  piston  valve  7<5,  with  the 
large  piston  77  on  one  end  and  the  small  piston  79  on  the 
other.  Chamber  E  is  always  connected  to  the  exhaust 


1O8 


SS 


28  THE   9J/2-INCH    AIR   PUMP 

passage  through  port  t  in  the  side  of  the  main  valve  bush- 
ing 75  so  that  this  piston  has  live  steam  on  the  steam  chest 
side  and  the  exhaust  on  the  other  at  all  times.  The  large 
piston  77  on  this  valve  76  has  live  steam  on  the  steam 
chest  side  and  the  office  of  the  reversing  valve  72  is  to  con- 
nect the  chamber  D  at  the  outside  end  of  77  with  the  live 
steam  or  with  the  exhaust  as  may  be  .required  to  move  76 
"back  and  forth.  When  D  is  connected  with  the  exhaust 
both  outside  ends  of  the  piston  valve  76  have  no  pressure 
on  them,  the  live  steam  between  the  heads  moves  77, 
Which  has  the  greatest  area,  away  from  the  live  steam 
pressure  towards  the  right.  When  the  main  steam  piston 
65  approaches  the  top  of  its  stroke  the  reversing  plate  dp 
strikes  the  shoulder  /  of  the  reversing  rod  71  which  is 
moved  up  carrying  the  reversing  valve  72  up ;  this  admits 
steam  into  port  g,  it  passes  along  the  side  of  the  bushing 
through  the  port  shown  into  chamber  D  at  the  outside  of 
piston  77,  which  having  live  steam  on  both  sides  of  it  is 
balanced.  Piston  79  has  live  steam  inside  and  exhaust 
outside,  so  it  moves  away  from  the  live  steam  drawing  the 
main  slide  valve  83  with  it.  This  movement  uncovers  port 
c,  live  steam  passes  down  on  top  of  the  piston  65,  the 
exhaust  cavity  of  83  connects  port  b  and  exhaust  port  d 
together  and  the  steam  from  bottom  end  of  cylinder  can 
pass  up  through  passage  or  port  b  to  the  exhaust  pipe. 
Steam  piston  65  will  then  make  the  down  stroke.  The 
position  of  all  the  valves  and  pistons  while  the  down 
stroke  is  being  made  is  shown  on  next  page.  When  close 
to  the  bottom  end  of  the  stroke,  the  reversing  plate  69 
catches  the  button  x  on  the  bottom  end  of  reversing  rod 
,71,  pulls  this  rod  down  and  with  it  reversing  valve  7^,  and 
connects  chamber  D  with  the  exhaust  through  ports  f  and 
h  in  the  side  of  bushing  75.  As  soon  as  the  pressure  is 
relieved,  live  steam  moves  piston  77  to  the  right,  drawing 
the  main  slide  valve  83  with  it;  all  steam  valves  are  then 
in  the  position  shown  on  page  27,  and  the  pump  begins  the 
upward  stroke.  The  main  valve  7  of  the  8-inch  pump  has 
live  steam  between  its  two  heads  or  pistons  at  the  same 


108 

85 


88 


104 


30  AIR    PUMP    CAPACITY 

time  and  this  tends  to  force  the  main  valve  up.  Piston  23 
is  used  to  overcome  the  advantage  the  large  piston  7  has 
and  force  it  down  for  the  up  stroke  of  the  piston  10.  With 
the  9 5^2 -inch  pump  the  differential  piston  76  is  moved  by 
changing  the  pressure  on  the  outside  of  piston  77;  this  is 
•done  by  the  reversing  valve  72.  The  angling  hole  in  cap 
nuts  20  and  74  serves  the  same  purpose  in  both  pumps — to 
balance  the  pressure  on  both  ends  of  the  reversing  rods  ;— 
this  opening  connects  with  the  top  end  of  steam  cylinder, 
down  past  the  reversing  valve  bushing.  The  reversing 
valve  72  in  the  9 ^2-inch  pump  performs  the  same  office  as 
valve  16  in  the  8-inch  pump,  but  the  reversing  valve  16 
admits  steam  over  the  top  of  16  through  port  a  to  piston 
23,  while  valve  72  admits  steam  under  the  bottom  end 
through  port  g  to  piston  77.  In  both  pumps  the  reversing 
rods  work  the  same  and  have  the  same  class  of  troubles. 
The  arrangement  of  the  steam  valves  in  the  9^-inch  pump 
is  much  superior  to  that  of  the  8-inch  in  every  way,  and  in 
addition  they  are  all  located  in  the  top  head  60.  In  case 
the  steam  valves  get  out  of  order,  by  changing  the  steam 
head  60  with  its  reversing  rod  71,  we  get  a  good  pump 
again. 

The  air  valves  in  the  9^-inch  pump  are  all  of  one  size 
and  have  the  same  lift— three  thirty-seconds  of  an  inch ; 
when  new  they  are  interchangeable  with  each  other.  The 
air  valve  cages  88  are  also  interchangeable.  As  these  air 
valves  act  the  same  as  those  of  the  8-inch  pump  when  the 
pump  is  working,  an  explanation  is  not  necessary. 

This  pump  is  9^  inches  bore  and  10  inches  stroke;  with 
140  pounds  of  steam  it  should  fill  a  main  reservoir  26^ 
i  inches  in  diameter  by  34  inches  long,  having  a  capacity  of 
about  15,000  cubic  inches  from  0  up  to  70  pounds  in  38 
seconds,  or  from  20  to  70  pounds  in  27  seconds.  You  can 
determine  whether  a  9^-inch  pump  is  in  good  order  by 
testing  it  and  noting  whether  it  can  do  this  work. 

An  8-inch  pump  should  pump  this  amount  of  air  from 
0  to  70  pounds  in  68  seconds,  and  from  20  to  70  pounds  in 
about  50  seconds,  using  steam  at  140  pounds. 


AIR    PUMP     CAPACITY  31 

The  11-inch  pump  is  much  the  same  in  construction  as 
the  9^-inch  pump.  It  is  11  inches  bore  and  12  inches 
stroke.  The  air  valves  are  much  larger,  but  have  the  same 
lift,  three  thirty-seconds  of  an  inch.  Its  operation  is  the 
same,  so  the  explanation  for  one  pump  will  do  for  the 
other.  The  capacity  is  much  greater,  as  100  strokes  of  the 
11-inch  pump  will  compress  48  cubic  feet  of  free  air,  while 
100  strokes  of  the  9^-inch  pump  will  'compress  36  cubic 
feet.  When  working  at  full  capacity  the  11-inch  pump 
will  compress  58  cubic  feet  of  free  air  per  minute  and  the 
9 Vz -inch  pump  38  cubic  feet. 

The  steam  end  of  the  pump  is  usually  oiled  by  a  sight 
feed  cup,  either  a  part  of  the  engine  cylinder  cup  or  a 
small  independent  one.  The  air  cylinder  can  be  satis- 
factorily oiled  by  an  attachment  to  the  oil  tank  of  the 
regular  cylinder  cup — see  illustration  and  description  on 
inside  of  front  cover.  This  sight  feed  device  is  a  down 
drop  through  air  instead  of  an  up  drop  through  water. 
When  operated,  the  regulating  valve  at  the  top  is  opened 
to  feed  a  few  drops  at  a  time,  not  more  than  ten,  and  at 
such  intervals  as  in  the  judgment  of  the  engineer  is 
required.  It  is  not  intended  for  a  continuous  feed,  that 
is  liable  to  give  too  much  oil,  this  is  as  bad  as  not 
enough. 


MAIN  VALVE  BUSHINQ 


1OO 


This  cut  shows 
the  position  of  re- 
versing valve  72 
when  pump  i  s 
making  the  up 
stroke. 

Port  s  in  main 
valve  bushing  is 
for  live  steam  to 
piston  77:  h  is  port 
for  exhaust  frcns 
this  piston;  f  con- 
nects with  exhaust 
port  d. 


This  cut  shows 
the  position  of  re- 
versing valve  72 
when  pump  is 
making  the  down 
•H  stroke. 

See  page  28. 


DEFECTS    OF   THE   AIR   PIJMP  33 


DEFECTS   OF   THE  AIR   PUMP 

Many  of  the  break-downs  and  defects  of  the  air  pump 
can  not  be  remedied  when  away  from  the  shop,  some  of 
them  can;  it  is  important  to  locate  the  nature  of  the  de- 
fect at  once  to  know  if  it  can  be  fixed-  then  and  there,  or  if 
another  air  brake  engine  will  be  needed  to  handle  the 
train  as  well  as  to  be  able  to  properly  report  the  defect 
on  the  work  book. 

In  the  case  of  any  disability  or  break  down  of  the 
steam  end  the  pump  usually  stops  altogether.  If  the  air 
end  is  out  of  order  it  will  not  make  any  air  or  at  the  best 
will  work  irregularly.  We  will  first  take  up  the  disabilities 
which  will  make  the  8-inch  pump  stop  altogether.  First 
see  that  a  full  supply  of  steam  goes  to  the  pump;  if  it 
does  not  the  trouble  may  be  in  the  governor. 

Leaky  gaskets  in  the  steam  head  or  leaks  past  the 
bushings  from  one  port  to  another  will  let  the  live  steam 
blow  into  the  exhaust  so  there  is  not  enough  pressure  to 
reverse  the  pump.  In  such  cases  you  can  hear  the  blow, 
the  pump  is  pretty  certain  to  stop  at  the  bottom  end  of  the 
stroke  and  stay  there.  If  the  copper  gasket  gets  cracked 
at  the  opening  where  steam  goes  through  from  port  h  into 
the  steam  head  the  live  steam  can  blow  on  one  side  into 
the  exhaust,  on  the  other  into  the  steam  cylinder;  this 
leak  does  not  always  stop  the  pump,  usually  it  does.  If 
anything  works  into  this  port  h  and  stops  it  up  so  steam 
can  not  pass  through  in  sufficient  volume  to  hold  proper 
pressure  for  the  reversing  piston  it  will  stop. 

Leaks  past  the  bushings  are  not  unusual;  when  once 
they  start,  the  steam  soon  finds  a  way  to  get  to  the  exhaust 
without  doing  its  work. 

When  the  packing  rings  and  valves  in  the  steam  end 
become  worn  the  oil  will  blow  into  the  exhaust  before  it 
has  oiled  all  the  moving  parts.  This  will  leave  reversing 
piston  23  so  dry  that  it  will  not  move  and  reverse  the 
position  of  main  steam  valve  7.  This  is  a  case  where 


34  AIR  PUMP    DEFECTS 

increasing  the  feed  of  oil  and  jarring  the  steam  head  with 
a  block  of  wood  will  usually  start  the  pump. 

A  piston  rod  broken  where  it  joins  piston  23  will  act 
much  the  same  way;  this  rod  has  been  known  to  get  stuck 
in  the  bottom  hole  in  the  bushing  and  hold  the  piston 
down.  The  small  hole  starting  in  the  side  of  this  bushing 
running  down  and  to  the  side  of  this  piston  rod  is  to  oil 
this  rod;  if  it  gets  stopped  up  it  should  be  opened.  Some- 
times the  top  of  reversing  piston  23  will  wear  to  a  steam 
tight  fit  against  the  cap  nut  21;  this  keeps  the  steam  off 
the  top  of  piston  23,  it  can  not  then  push  it  and  main 
steam  valve  7  down.  An  examination  of  these  surfaces, 
and  if  necessary  nicking  the  smooth  surfaces  so  the  steam 
can  get  in,  will  remedy  this. 

When  the  reversing  plate  18  gets  loose,  or  the  button  x 
on  the  reversing  valve  rod  17  breaks  off,  the  pump  will 
reverse  at  the  top  end  of  its  stroke,  but  not  at  the  bottom 
and  will  stop  at  the  bottom  end  of  its  stroke.  If  the  steam 
is  now  shut  off  and  the  reversing  valve  allowed  to  settle 
down  by  gravity  when  the  steam  is  turned  on,  the  pump 
will  make  another  double  stroke  and  stop  again.  Taking 
off  the  cap  nut  20  and  raising  up  the  reversing  rod  will 
show  whether  this  is  the  trouble.  In  this  case  a  spare  rod 
17  comes  handy.  If  the  plate  18  is  loose  the  steam  head 
will  have  to  come  off  to  get  at  the  plate.  If  one  of  the 
nuts  58  holding  the  air  piston  on  the  piston  rod  works  off, 
or  a  piece  of  it  breaks  off — these  nuts  split  sometimes — 
and  gets  under  the  air  piston  so  that  it  can  not  come  clear 
down  to  move  the  reversing  rod  and  valve  properly,  that 
will  stop  the  pump.  Take  out  the  plug  59  in  the  bottom 
head  of  the  air  cylinder  or  the  entire  head,  and  this  trouble 
can  be  located.  If  the  nuts  work  off  either  end  of  main 
steam  valve  7  the  pump  is  liable  to  stop  at  once.  If  the 
stop  pin  50  below  the  small  piston  7  breaks  off  so  the  small 
piston  gets  below  the  bushing  26  and  sticks,  the  pump 
will  stop  until  this  valve  can  be  moved  up. 

Stoppage  of  the  pump  may  be  caused  by  an  obstruc- 
tion working  into  some  of  the  small  steam  ports,  closing 


AIR    PUMP    DEFECTS  35 

them  up,  especially  port  h.  Taking  off  the  cap  nut  21 
after  steam  has  been  shut  off  and  all  the  valves  settled 
down  will  locate  this  difficulty,  as  when  all  the  passages 
are  free  the  steam  will  come  out  through  port  a  over  the 
reversing  piston  23.  This  same  test  will  show  whether 
governor  is  open  for  steam  but  is  not  as  reliable  as  break- 
ing the  joint  between  the  governor  and  pump.  We  will 
speak  of  the  governor  later  on. 

As  the  reversing  rods,  plates  and  valves  are  of  the 
same  pattern  in  the  11-inch,  8-inch  and  9^-inch  pumps, 
the  failures  of  any  of  these  parts  affect  all  these  pumps 
alike.  With  this  exception  the  steam  end  of  the  9^-inch 
pump  gives  very  little  trouble  if  the  joints  and  gaskets  are 
in  good  order. 

Nearly  all  the  blows  of  steam  when  the  pump  is  at 
work  take  place  when  the  steam  piston  is  making  the 
upward  stroke.  At  that  time  the  steam  can  blow  past  the 
steam  piston  packing  rings  for  when  on  the  down  stroke 
the  condensed  water  laying  on  top  of  this  piston  will  pre- 
vent much  steam  getting  by  the  rings ;  on  the  up  stroke 
there  is  nothing  of  the  kind  to  hold  the  steam  back.  On 
the  up  stroke  live  steam  is  on  top  of  reversing  piston  23  so 
it  can  blow  into  the  exhaust,  on  the  down  stroke  it  is  ex- 
haust on  both  sides.  With  the  differential  piston  76  of  the 
9^2-inch  exhaust  steam  is  on  both  ends  on  up  stroke. 

A  blow  past  these  main  valves  of  either  pump  is  so 
nearly  like  a  blow  past  the  steam  piston  that  an  examina- 
tion is  necessary  to  determine  its  location.  A  bad  blow 
coming  all  at  once  is  a  good  indication  of  a  broken 
packing  ring  or  a  leak  started  through  one  of  the  copper 
gaskets. 

If  the  top  end  of  the  reversing  rod  is  not  a  steam  tight 
fit  in  its  cap  nut  in  the  8-inch  or  74  in  the  9^-inch  and 
11-inch  pump,  steam  will  blow  past  there  steadily  on  the  up 
stroke;  passing  through  the  small  hole  drilled  obliquely 
through  the  cap  nut,  then  down  past  the  reversing  valve 
bushing  and  into  the  upper  end  of  steam  cylinder  which 
on  the  up  stroke  is  connected  to  the  exhaust.  It  can  not 


36  LEAKY    AIR    VALVES 

blow  on  the  clown  stroke,  as  at  that  time  live  steam  is  in 
the  top  end  of  the  cylinder.  Very  few  of  these  reversing 
rods  are  steam  tight  in  the  cap  nuts.  This  opening  between 
the  steam  space  above  the  piston  and  top  of  cap  nut  is 
necessary  to  balance  the  pressures  on  the  reversing  rod 
so  it  will  not  move  while  the  pump  is  making  its  stroke. 

If  the  reversing  rod  gets  bent  so  it  catches  on  the 
reversing  plate  or  the  button  catches  on  the  side  of  the 
hole  in  the  piston  rod,  the  pump  will  reverse  before  it 
completes  its  stroke.  A  pump  that  reverses  too  soon  in  its 
stroke  will  pump  very  little  air  into  the  main  reservoir. 

A  difficulty  in  the  air  end  of  the  pump  will  usually  give 
notice  at  once  by  a  quick  stroke  one  way  and  a  slow  stroke 
the  other,  which  may  be  caused  by  several  defects.  If  air 
from  main  reservoir  leaks  past  a  discharge  valve  it  will 
fill  that  end  of  the  cylinder  with  high  pressure  air  so  the 
air  piston  will  move  away  from  it  quickly  and  towards  it 
slowly.  In  such  a  case  the  inlet  valve  cannot  lift — no  air 
will  be  drawn  in  at  that  end.  If  the  inlet  valve  leaks  an 
examination  will  disclose  it  with  the  8-inch  pump.  With 
the  9^2  and  11-inch  pumps  it  is  not  so  easy,  as  the  air 
passing  out  of  one  inlet  valve  will  pass  to  the  other  and 
give  it  the  signs  of  a  poor  suction  there.  Improper  lift  of 
valves  will  make  a  pump  move  faster  one  way  than  the 
other.  If  the  lift  of  an  inlet  valve  is  too  small,  that  end  of 
the  cylinder  may  not  fill  with  air  so  the  piston  will  not 
meet  with  so  much  resistance  in  compressing  the  air. 
If  the  lift  of  a  delivery  valve  is  too  small  the  piston  will 
move  very  slowly  at  the  last  part  of  the  stroke;  it  has  to 
wait  for  the  compressed  air  to  pass  through  the  small 
discharge  opening.  It  will  show  more  difference  in 
relative  speed  when  the  air  pressure  is  low. 

The  lift  of  the  receiving  valves  31  and  33  of  the  8-inch 
pump  should  be  one-eighth  of  an  inch,  of  the  discharge 
valves  30  and  32  three  thirty-seconds  of  an  inch.  This  lift 
is  very  soon  changed  by  the  wear  of  the  valves  and  the 
seats;  too  much  lift  of  discharge  valves  will  make  the 
pump  pound,  as  well  as  wasting  main  reservoir  air  by 


AIR    PUMP    DEFECTS  37 

allowing  some  of  it  to  flow  back  into  the  cylinder  before 
the  valves  can  seat.  To  test  for  a  leak  in  the  bottom 
discharge  valve,  pump  up  full  pressure,  stop  the  pump, 
take  out  the  plug  in  the  bottom  head — air  will  blow  out 
there  steadily  from  a  leak.  To  test  for  a  leak  in  top  dis- 
charge valve  leave  this  bottom  plug  out  and  open  the  oil 
cup  on  top  end  of  cylinder;  see  if  air  blows  out  there 
steady;  if  so,  it  comes  from  top  valve.  You  should  have 
both  ends  open  as  the  air  might  leak  past  piston  packing 
and  appear  to  come  from  the  wrong  end. 

Leaky  packing  rings,  leaky  valves,  choked  air  passages, 
all  tend  to  make  the  pump  run  hot.  Running  the  purnp 
at  too  high  a  speed  is  generally  the  trouble  in  the  first 
instance.  When  once  it  has  been  very  hot  the  packing 
rings  contract  and  do  not  fill  the  cylinder;  the  valve  bush- 
ings leak  and  the  oil  burns  on  the  inside  of  passages  and 
make  a  bad  matter  worse. 

The  Westinghouse  Company  are  now  making  a  cross- 
compound  air  pump  in  which  the  high  pressure  steam 
piston  operates  the  low  pressure  air  piston;  the  steam 
when  exhausted  from  this  cylinder  then  passes  across  to 
the  other  end  of  the  low  pressure  steam  cylinder  and 
operates  the  low  pressure  steam  piston  and  the  high 
pressure  air  piston.  A  diagrammatic  view  of  this  pump 
is  shown;  as  by  this  means  the  steam  and  air  passages  can 
be  more  clearly  traced.  The  reversing  rod  21  and  valve 
22  are  operated  by  the  reversing  plate  18  at  the  end  of  the 
stroke  of  the  high  pressure  steam  piston  7  in  the  same 
manner  as  the  9^-inch  pump. 

The  first  design  of  this  pump  had  a  differential  piston 
and  slide  valve  to  open  and  close  the  steam  and  exhaust 
ports  for  the  steam  cylinders;  very  few  of  this  pattern 
are  in  service.  A  later  design  has  a  piston  valve  instead 
of  a  differential  piston  and  slide  valve.  This  piston  valve 
consists  of  five  pistons,  a  large  one  at  one  end  and  a  small 
one  at  the  other  that  have  the  same  duties  as  the  differ- 
ential pistons  in  the  other  pumps,  between  these  two  and 
pistons  are  three  intermediate  pistons  of  the  same  size 


38  CROSS -COM  POUND     AIR    PUMP 

that  open  and  close  communication  between  the^  ports 
leading  to  and  from  the  steam  cylinders. 

The  same  type  of  reversing  valve  is  used,  except  that 
the  exhaust  cavity  is  near  the  top,  in  the  old  one  it  is 
near  the  bottom. 

Steam  from  the  boiler  after  passing  the  governor, 
comes  in  at  the  side,  passes  through  port  a  up  and  across 
the  steam  head  into  ports  b  inside  the  large  piston  at 
one  end  and  inside  the  small  piston  at  the  other;  the 
diagrammatic  view  shows  all  these  ports.  Live  steam  also 
passes  in  at  port  k  around  the  reversing  valve  22. 

As  the  high  pressure  steam  piston  must  make  at  least 
one  full  stroke  before  any  steam  can  pass  into  the  low 
pressure  cylinder,  in  this  explanation  we  will  consider 
that  high  pressure  piston  7  has  made  its  first  up  stroke 
moved  the  reversing  valve  to  its  top  position  and  opened 
steam  port  n  so  live  steam  has  passed  into  cylinder  D 
and  forced  piston  valve  25  to  the  left  as  shown;  E  at  the 
small  end  is  always  in  connection  with  the  exhaust  e 
through  port  o.  Live  steam  now  flows  through  port  c  on 
top  of  piston  7  forcing  it  down.  Steam  under  piston  7 
that  moved  it  up  in  making  the  previous  stroke  can  now 
pass  through  port  g  from  the  bottom  of  this  cylinder  up 
into  cavity  i  between  the  first  and  second  intermediate 
pistons,  thence  down  through  port  f  into  the  bottom  of 
the  low  pressure  cylinder  under  piston  8,  forcing  it  up; 
any  steam  above  this  piston  can  escape  through  port  d 
and  cavity  h  between  the  second  and  third  intermediate 
pistons  into  exhaust  port  e  and  the  atmosphere. 

When  piston  7  is  about  to  complete  its  down  stroke 
it  moves  the  reversing  rod  and  valve  down  also,  this  closes 
port  n  and  connects  exhaust  port  m  from  cylinder  D  with 
the  exhaust  port  /  leading  to  e  so  the  steam  in  D  escapes 
to  the  exhaust,  live  steam  pressure  in  cavity  b  at  once 
moves  piston  25  to  the  right  connecting  ports  c  and  d 
through  cavity  ht  the  steam  above  piston  7  now  passes  in 
above  piston  8,  live  steam  from  b  flows  through  port  g 
into  the  bottom  end  of  high  pressure  cylinder  and  piston 


STEAM  INLET 


40  33 

DIAGRAM  OF  THE  CROSS  COMPOUND  PUMP,  DOWN 
STROKE,    HIGH-PRESSURE-STEAM    SIDE. 


40  CROSS-COMPOUND    AIR    PUMP 

7  makes  the  up  stroke,  piston  8  makes  the  corresponding 
down  stroke,  the  steam  below  it  escaping  to  the  exhaust 
through  port  /  and  cavity  i  to  c.  Port  z  is  a  balancing 
port  to  equalize  the  pressure  on  the  top  and  bottom  of  the 
reversing  rod  21. 

The  low  pressure  steam  cylinder  has  three  by-pass 
grooves  in  it  at  each  end  that  are  open  just  as  the  low 
pressure  piston  completes  its  full  stroke  and  allow  steam 
to  pass  around  the  piston  from  the  pressure  side  to  the 
exhaust  side  of  piston  8.  The  steam  pistons  move  at  the 
same  time,  but  in  opposite  directions,  the  high  pressure 
piston  moves  the  reversing  rod  and  valve  so  this  piston 
must  make  a  complete  stroke  each  time  to  operate  the 
piston  valve  25  and  change  the  course  of  the  live  and 
exhaust  steam. 

The  course  of  the  air  through  the  air  cylinders  and 
valves  from  the  atmosphere  to  the  low  pressure  cylinder, 
then  across  into  the  high  pressure  air  cylinder  is  shown 
by  the  small  arrows  pointing  in  the  direction  the  air  is 
flowing.  When  the  low  pressure  air  piston  9  made  its 
up  stroke  any  air  above  it  was  forced  out  past  the  upper 
intermediate  valves  39  behind  the  moving  high  pressure 
piston  10  and  air  below  piston  10  passes  out  by  discharge 
valve  42  to  the  main  reservoir.  In  the  diagrammatic  view 
low  pressure  air  piston  9  is  shown  making  the  down 
stroke,  air  from  the  atmosphere  is  flowing  in  at  the  upper 
air  inlet  thence  by  the  inlet  valves  37  and  port  sf  and  rill- 
ing the  air  cylinder  behind  the  moving  piston  9,  inter- 
mediate valves  39  prevent  any  air  coming  back  from  the 
high  pressure  air  cylinder.  The  air  below  piston  9  is 
now  compressed  till  it  will  pass  out  through  port  t  past 
intermediate  valves  40  into  the  high  pressure  cylinder 
below  piston  10  that  is  making  its  up  stroke;  the  air  above 
it  is  compressed  till  it  exceeds  the  main  reservoir  pressure 
and  raises  discharge  valve  41,  passing  out  through  w  to 
the  main  reservoir. 

The  inlet  and  intermediate  air  valves  are  double,  as 
39  and  40  show,  37  and  38  being  set  the  other  way  across 


PUMP     GOVERNOR  41 

the  pump;  the  sectional  view  shows  only  one  of  the  pair. 
During  the  stroke  of  the  pistons  the  intermediate  pressure 
being  that  between  the  low  and  high  pressure  air  pistons 
reaches  about  40  pounds. 

The  high  pressure  steam  piston  7  has  a  diameter  of 
85^  inches,  low  pressure  steam  piston  8  is  14^2  inches; 
all  pistons  have  a  stroke  of  12  inches.  The  low  pressure 
air  piston  is  14^  inches  and  the  high  pressure  air  piston 
9  inches  in  diameter. 

The  capacity  of  this  pump  is  131  cubic  feet  of  free 
air  per  minute,  as  against  58  for  the  11-inch  pump  work- 
ing under  the  same  condition. 


THE    PUMP    GOVERNOR 

The  duty  of  the  pump  governor  is  to  shut  off  the 
steam  from  the  air  pump  when  the  air  pressure  has  reached 
the  standard  desired.  Where  only  one  pressure  is  to  be 
controlled,  the  single  governor  is  used ;  if  more  than  one 
pressure,  the  duplex  governor  is  used.  The  steam  valve 
and  its  air  piston  are  the  same  with  both  the  duplex  and 
single  governors,  but  one  or  two  air  tops  are  used,  accord- 
ing to  the  number  of  air  pressures  controlled. 

It  is  located  close  to  the  pump  on  the  steam  pipe,  at 
the  union  connection  70  the  air  that  operates  the  governor 
enters,  and  is  under  the  diaphram  67.  This  diaphram  is 
held  down  by  the  regulating  spring  66,  which  can  be 
adjusted  by  the  regulating  nut  65. 

We  will  suppose  that  the  spring  66  has  been  adjusted 
to  hold  the  diaphram  down  against  the  air  pressure  of  90 
pounds  and  no  more.  When  the  air  pressure  exceeds  90 
pounds  the  diaphram  will  be  raised  against  the  resistance 
of  the  spring;  this  will  raise  the  air  valve,  air  will  flow  in 
on  top  of  the  air  piston  53  and  force  it  down,  moving 
steam  valve  down  to  its  seat  and  closing  the  steam  sup- 
ply to  the  pump,  which  will  stop  it. 

As  soon  as  the  air  pressure  falls  so  the  regulating, 
spring  66  can  move  the  diaphram  down  and  close  the  air 


42 


PUMP    GOVERNOR 


PUMP  GOVERNOR 
•  DETAILS.,  PL*!*  EK 

team-Valve  Body 


Cylinder  Cap. 
Governor  Pisto 
Piston  Packing  Ring. 


valve  the  air  pressure  above  the  piston  drops,  and  the 
steam  valve  is  opened  allowing  the  pump  to  take  steam 
again.  With  the  duplex  governor  the  regulating  spring  of 
one  air  top  can  be  adjusted  for  one  pressure  and  the  other 
spring  for  another  pressure.  Thus  the  pressure  carried 
depends  on  which  side  of  the  governor  is  in  operation. 
There  are  several  causes  which  will  prevent  the  gov- 
ernor from  shutting  off  the  steam  from  the  pump  when  the 
maximum  -air  pressure  is  obtained.  If  the  regulating 

spring  is  screwed  down  too 
tight  it  will  not  allow  the 
diaphram  to  raise  and  lift 
the  air  valve  off  its  seat.  If 
too  much  oil  is  used  in  air 
end  of  pump  the  air  valve 
gets  gummed  up  where  it 
rests  on  its  seat  so  air  can 
not  get  through  after  air 
valve  raises.  This  is  the 
most  common  cause  of  the 
pressure  getting  higher 
than  the  governor  is  set 
for.  To  cure  this  trouble 
take  out  diaphram  and 
clean  off  air  valve  and  its 
seat  so  air  can  get  through 
freely  when  air  valve  raises- 
If  the  air  leaks  past  piston 
as  fast  as  it  comes  through 
air  valve,  the  piston  will 
not  be  moved  down  as 
there  will  be  no  pressure 
above  piston.  Putting  in  a 
tight  packing  ring  cures 
this  unless  the  cylinder  is 

worn  out  of  true.  If  the  governor  piston  sticks  so  air 
pressure  will  not  force  it  down,  steam  will  not  be  shut 
off.  If  the  waste  pipe  in  the  side  of  steam  end  of  gov- 


>.     Governor-Piston  Nut.      J 
!.  .  Governor-Piston  Spring^ 
.     Steam  -  Valve   Cylinder 
iv-    Diaphragm  Boily. 

3.  Spring  Box. 

4.  Cap  Nut. 

5.  Regulating  Nut. 

6.  Regulating  Spring. 

7.  Diaphragm  complete; 

8.  Diaphragm  Ri 


PUMP     GOVERNOR  43 

ernor  is  stopped  up  so  steam  or  air  is  confined  below 
piston,  the  governor  will  not  shut  off  at  any  pressure. 
This  waste  pipe  may  be  smashed  out  flat  so  nothing  can 
pass  through  it,  in  cold  weather  it  will  freeze  solid  full 
at  the  bottom  end  which  will  keep  the  air  piston  held  up. 
If  anything  gets  in  over  diaphram  so  it  cannot  raise,  that 
will  hold  air  valve  shut  so  air  cannot  get  on  piston  to  shut 
off  steam  valve.  If  valves  and  seats  are  kept  clean,  and 
all  parts  allowed  to  move  as  they  should,  governor  will 
work  accurately.  In  case  the  governor  shuts  off  the  steam 
with  less  than  the  standard  pressure  you  are  likely  to  find 
there  is  dirt  or  a  scale  holding  the  air  valve  off  its  seat 
so  air  can  get  through  on  top  of  piston  steadily,  in  which 
case  the  governor  will  shut  off  steam  as  soon  as  air 
pressure  on  the  top  of  governor  piston  will  more  than 
balance  steam  pressure  on  steam  valve.  If  this  air  valve 
seat  is  injured  so  it  leaks,  or  a  new  valve  has  been  put  in 
that  is  too  short  to  make  a  good  joint,  a  very  low  air 
pressure,  less  than  forty  pounds,  will  shut  off  the  steam. 
A  broken  regulating  spring  will  also  do  this. 

Sometimes  the  pump  will  not  start  up  soon  after  the 
air  pressure  in  the  governor  has  been  reduced  below  that 
the  governor  diaphram  is  set  at.  This  is  because  when  the 
air  valve  closes,  the  air  is  shut  up  in  cylinder  over  gov- 
ernor piston  and  must  leak  out  before  piston  can  raise  and 
open  steam  valve.  The  old  type  of  governor  D-9  had  this 
trouble,  .but  the  new  style  of  governor  E-8  has  a  small 
blow  hole  drilled  in  the  side  of  62,  below  air  valve  seat, 
which  lets  enough  air  escape  after  standard  pressure  is 
reached  to  keep  pump  running  steadily. 

To  find  if  the  trouble  is  in  the  governor  when  the 
pump  will  not  start,  open  both  drip  cocks  in  the  9^-inch 
or  11-inch  pumps,  or  break  the  joint  between  the  governor 
and  8-inch  pump ;  if  live  steam  comes  out  freely  the  gov- 
ernor is  not  at  fault.  In  such  a  case  shut  off  steam  at  the 
boiler,  wait  a  few  seconds  till  steam  is  out  of  pump  and 
turn  it  on  again,  if  the  live  steam  blows  out  freely,  the 
trouble  is  in  the  pump.  • 


44  PUMP    GOVERNOR 

With  the  single  top  governor  and  a  brake  valve  using  a 
feed  valve  to  regulate  the  brake  pipe  pressure,  main  reser- 
voir air  is  used  to  operate  the  governor,  with  some  types 
of  brake  valves  like  the  old  D-8  or  the  N.  Y.  brake  valve 
brake  pipe  pressure  operates  the  governor.  With  the 
duplex  governor  one  side  is  usually  piped  to  the  main 
reservoir  direct,  the  other  side,  in  some  cases,  uses  brake 
pipe  air.  With  the  high  speed  brake,  one  side  is  set  for 
90  pounds,  the  main  reservoir  pressure  used  with  the 
•ordinary  brake  pipe  pressure  of  70  pounds;  the  other  side 
for  the  higher  pressure  needed  to  release  brakes,  using 
110  pounds.  In  such  cases  there  is  a  stop  cock  in  the  90 
pound  side  air  pipe,  which  is  to  be  closed  to  cut  out  that 
side  when  the  higher  pressure  is  used.  The  N.  Y.  brake 
uses  a  triple  governor. 

There  is  also  a  method  of  piping  which  allows  of  two 
main  reservoir  pressures  being  used,  one  on  release  and 
running  position  of  the  F-6  brake  valve  and  a  higher  one 
with  the  valve  on  lap  and  application  positions.  The  90 
pound  side  is  piped  to  the  port  /  in  the  1892  model  brake 
valve  at  a  point  just  above  the  figure  62 — see  the  cut  of 
this  valve  farther  on.  When  the  rotary  is  in  full  release 
or  running  position,  main  reservoir  air  can  come  freely 
into  this  port  and  operate  the  governor  at  a  pressure  of 
90  pounds.  During  a  brake  application  this  port  /  is  closed 
by  the  rotary  and  the  air  pressure  there  soon  equalizes 
with  the  brake  pipe. 

The  90  pound  side  of  the  governor  does  not  then  con- 
trol the  pump  and  the  high  pressure  side  which  is  con- 
nected directly  to  the  main  reservoir  and  adjusted  for  a 
pressure  higher  than  90  pounds,  usually  110  pounds,  allows 
the  pump  to  run  and  raise  the  main  reservoir  pressure  so 
as  to  have  a  good  stiff  excess  to  release  brakes. 

There  is  also  a  method  of  piping  the  S  F  duplex  gov- 
ernor with  the  E.  T.  brake  to  control  the  amount  of  excess 
pressure  regardless  of  what  the  brake  pipe  pressure  may 
be.  One  side  is  piped  to  the  main  reservoir  direct  at 
MR,  and  set  120  or  130  pounds,  according  to  what  the 


PUMP    GOVERNOR 


45 


maximum  main  reservoir  pressure  is  to  be.  The  other 
side  has  a  light  spring  27  over  the  diaphram  that  has  the 
proper  tension  to  hold  the  diaphram  21  down  for  the 


THE  SF-4  PUMP  GOVERNOR 


excess  desired.  At  A  B  V  main  reservoir  air  from  the 
brake  valve  conies  in  under  the  diaphram  at  d  from  the 
automatic  brake  valve  in  full  release,  running  and  holding 
positions.  The  position  of  the  brake  valve  regulates  the 
flow  of  air  to  the  excess  pressure  side.  At  FVP  feed  valve 
air  at  the  reduced  pressure  comes  in  above  the  diaphram, 
and  its  pressure  is  added  to  that  of  the  spring  27  so  that 
we  have  70  pounds  brake  pipe  plus  that  of  the  spring — 
say  20  pounds — so  that  when  the  main  reservoir  air  in  d 


46  PUMP     GOVERNOR 

can  overbalance  the  presure  of  70_|_20  above  the  diaphram, 
the  diaphram  will  raise  the  pin  valve  and  admit  air  over 
the  governor  piston  and  close  the  steam  valve  5.  This 
will  operate  the  same  at  any  other  brake  pipe  pressure; 
so  there  will  be  the  same  excess,  depending  on  the  adjust- 
ment of  the  spring  27.  Air  passes  in  at  ABV  only  in 
release,  running  and  holding  positions  of  the  type  H 
brake  valve.  When  the  brake  valve  is  moved  to  lap  or 
beyond  the  air  is  cut  off  from  under  the  diaphram  at  d 
and  the  pressure  at  a  and  spring  19  control  the  pump. 
A  peculiarity  of  operation  of  this  governor  is  that  when 
charging  up  a  long  train  through  the  brake  valve  in  run- 
ning position,  if  there  is  more  than  20  pounds  difference 
between  main  reservoir  and  brake  pipe  pressures  the  gov- 
ernor will  stop  the  pump.  In  such  a  case  put  the  brake 
valve  in  full  release  and  the  pump  will  soon  start. 


AIR  BRAKE  CATECHISM 


1.  Q.  What  are  the  essential  parts  of  the  automatic 
brake  and  what  service  does  each  part  perform? 

A.  The  air  pump,  the  main  reservoir,  the  engineer's 
brake  valves,  automatic,  independent  and  straight  air,  the 
brake  pipe  with  its  hose,  couplings,  and  angle  cocks,  the 
auxiliary  reservoir,  the  triple  valve,  the  brake  cylinder, 
the  gage  and  the  pump  governor.  The  air  pump  com- 
presses the  air  for  setting  and  releasing  the  brake;  the 
main  reservoir  is  used  to  store  a  supply  of  air  for  charging 
the  brake  pipe  and  auxiliary  reservoirs  when  empty,  as  well 
as  to  hold  the  supply  for  increasing  the  brake  pipe  pressure 
when  the  brake  is  to  be  released  and  to  charge  the  brake 
pipe  and  auxiliaries  ready  for  the  next  application ;  the 
automatic  brake  valve  governs  the  passage  of  the  air  from 
the  main  reservoir  to  the  brake  pipe,  from  the  brake  pipe 
to  the  atmosphere,  or  stops  the  flow  of  air  through  it  in 
any  direction.  The  brake  can  be  set  gradually  or  full  on, 
held  set  or  released,  when  this  valve  is  properly  handled 
by  the  engineer.  The  feed  valve  controls  the  supply  of  air 
to  the  brake  pipe  in  running  position  of  brake  valve  and 
regulates  its  pressure ;  the  straight  air  brake  valve  passes 
main  reservoir  air,  reduced  to  45  pounds,  to  and  from  the 
brake  cylinders  direct.  The  brake  pipe,  with  its  hose  and 
couplings,  extends  from  the  brake  valve  to  the  last  air 
brake  car,  and  supplies  each  auxiliary  reservoir  with  air 
for  setting  the  brake.  It  is  also  a  means  of  communication 
from  the  engineer's  brake  valve  to  each  triple  valve,  and 
from  one  triple  valve  to  another  in  the  quick  action  or 
emergency  application. 

Each  brake  has  an  auxiliary  reservoir  in  which  the  air 
is  stored  for  operating  it  to  set.  The  triple  valve  consists 
of  three  separate  valves  and  is  connected  to  the  brake 
pipe,  auxiliary  and  brake  cylinder;  it  is  used  to  control 
the  charging  of  the  auxiliary  with  air  and  regulate  the  time 


48  INSPECTION    AT   ENGINE    HOUSE 

in  which  this  is  done,  to  open  a  valve  to  admit  air  from 
auxiliary  to  brake  cylinder  to  set  the  brake,  or  by  another 
movement  to  close  this  valve  and  open  the  exhaust  port 
so  air  can  get  out  of  brake  cylinder  to  the  atmosphere  and 
release  the  brake.  Thus  the  functions  of  the  triple  valve 
are  three-fold,  to  charge  the  auxiliary,  set  the  brake  and 
release  it.  The  triple  valve  is  operated  by  a  variation  of 
pressures  between  the  brake  pipe  and  auxiliary;  this  varia- 
tion is  controlled  by  the  brake  valve.  The  brake  cylinder, 
with  its  piston  connected  to  the  brake  levers,  beams  and 
shoes,  sets  the  brake  when  the  triple  valve  lets  air  into  it. 
The  gage  shows  with  the  red  hand  main  reservoir  press- 
ure, with  black  hand  pressure  in  the  brake  valve  above 
the  equalizing  piston  and  in  brake  valve  reservoir;  when 
brake  valve  is  in  full  release,  running,  or  holding  position 
it  also  shows  brake  pipe  pressure.  The  pump  governor 
is  located  in  the  steam  pipe  to  pump;  it  is  operated  by  air 
pressure  and  shuts  off  steam  from  the  pump  when  the  air 
pressure  reaches  the  standard  amount  carried. 

In  addition  to  these  essential  parts  there  is  the  pressure 
retaining  valve  that  is  attached  to  the  exhaust  outlet  of 
the  triple  valve  and  controls  the  flow  of  air  away  from  the 
brake  cylinder  when  the  triple  valve  is  in  release  position; 
the  conductor's  valve  that  when  opened  reduces  the  brake 
pipe  pressure  and  applies  the  brake,  the  release  valve  or 
bleeder  connected  to  the  auxiliary  reservoir  used  to  reduce 
the  auxiliary  pressure  and  release  a  single  brake.  A 
separate  valve  and  its  reservoir  called  the  distributing 
valve  is  used  on  locomotives  and  performs  the  duties  of 
the  triple  valve  by  applying  and  releasing  the  locomotive 
"brake.  A  high  speed  reducing  valve  is  used  on  coaches. 

2.  Q.  What  are  the  duties  of  an  engineer  as  to  his  air 
brake  equipment  when  leaving  the  roundhouse? 

A.  To  start  his  pump  slowly  and  increase  its  speed 
after  15  or  20  pounds  of  air  have  picked  up;  to  be  sure 
that  pump  is  in  good  order  and  will  pump  a  full  supply 
of  air  promptly;  to  know  that  governor  shuts  off  the 
pump  when  the  proper  pressure  is  reached  and  not  before, 


TESTING    FOR     LEAKS  49 

and  allows  it  to  start  promptly;  to  see  that  lubricator  has 
oil  enough  in  it  for  the  trip;  to  know  that  there  is  no 
water  in  the  main  reservoir,  drain  cup,  triple  valves, 
auxiliary  reservoirs  or  distributing  valve,  to  test  all  joints 
in  piping,  also  brake  valve  and  triple  valves  for  leaks, 
and  have  leaks  made  tight;  to  see  that  tender  and  driver 
brake  pistons  have  the  proper  travel  and  do  not  leak  off 
when  set ;  to  test  the  air  signal  if  one  is  used. 

3.  Q.     Why  must  the  pump  be  started  slowly,  oil  used 
cautiously,  triple  valves,  reservoirs  and  tender  strainers  be 
drained,  and  how  often? 

A.  The  pump  must  be  started  slowly  to  allow  the 
condensed  water  to  get  out  of  steam  end,  and  run  slowly 
till  the  air  pressure  rises,  or  the  piston  will  strike  the 
heads  of  air  cylinder.  The  triple  valves,  reservoirs  and 
strainers,  or  drain  cups,  should  be  drained  every  day  in 
cold  weather,  once  a  week  in  warm  weather.  Oil  should 
be  used  sparingly  in  air  end  of  pump.  It  should  never  be 
put  in  through  the  air  inlets  of  the  pump,  as  it  soon 
collects  dirt  and  chokes  up  the  air  passages,  which  helps- 
to  make  the  pump  run  hot. 

4.  Q.     How  do  you  test  for  leaks  in  the  engine  equip- 
ment ? 

A.  When  full  pressure  is  obtained — 70  in  brake  pipe, 
90  in  main  reservoir — shut  off  pump,  place  valve  on  lap; 
if  red  hand  drops  and  black  hand  is  stationary,  it  is  a  sign 
of  a  leak  somewhere  in  main  reservoir  line,  which  begins 
at  valves  in  pump  and  ends  at  brake  valve.  It  may  be  in 
joints  of  piping,  in  main  reservoir  drip  plug,  in  the  air 
signal  line,  in  valves  of  pump  or  brake  valve.  If  there  is 
an  air  sander  or  air  bell  ringer  on  the  engine  their  valves 
are  liable  to  leak.  If  main  reservoir  pressure  falls  rapidly 
when  you  are  sure  it  is  not  going  into  brake  pipe  under 
rotary,  examine  each  of  the  places  mentioned.  With  the 
use  of  the  cut-out  cock  under  brake  valve  a  leak  under 
rotary  is  soon  detected.  Set  the  brake  full  on,  place  the 
valve  on  lap,  shut  the  cut-out  cock;  if  rotary  leaks  inta 
brake  pipe  the  black  hand  will  soon  show  same  pressure 


50  TESTING     FOR     LEAKS 

red  one  does ;  if  rotary  is  tight  and  air  leaks  out  of  brake 
pipe  the  black  hand  will  drop.  With  a  leak  in  brake  pipe 
of  engine  or  tender  and  cut-out  cock  shut,  the  brake  will 
set  with  valve  on  lap,  and  cut-out  cock  open  the  black  hand 
will  fall  slowly.  For  a  leak  in  signal  line  shut  the  cut- 
out cock  next  the  reducing  valve;  a  leak  here  will  make 
the  whistle  blow.  Using  a  torch  or  putting  soapsuds  on 
a  suspected  leak  will  generally  locate  air  blowing  out 
there. 

5.  Q.     Why  must  there  be  no  leaks  in  your  brake  pipe 
or  any  other  part  of  your  air  brake  supply? 

A.  If  brake  pipe  leaks,  brake  will  continue  to  set 
tighter  when  brake  valve  is  put  on  lap,  and  stop  the  train 
before  you  want  it  to,  so  that  it  is  necessary  to  let  it  off 
and  make  another  application  for  an  ordinary  stop.  If 
cars  are  cut  off  from  engine,  they  must  be  bled  at  once  if 
their  brake  pipe  or  angle  cocks  leak.  Brake  pipes  some- 
times get  worn  through  where  they  rest  or  rub  against 
something,  so  they  are  tight  when  standing  still  and  leak 
'when  moving  or  shaken  around.  This  leak  sets  the  brake 
when  train  is  in  motion,  and  no  leak  can  be  heard  when 
standing  still.  Jar  the  pipes  a  little  when  inspecting  the 
engine  to  locate  this  leak.  Sometimes  the  brake  levers 
strike  the  end  of  plug  in  stop  cock  and  push  it  in  so  it  will 
leak  when  brake  is  applied. 

6.  Q.     Why  must  all  hose  couplings  be  hung  up  prop- 
erly when  not  in  use?     Why  should  they  always  be  blown 
out  at  rear  of  tender  before   uniting  to   other  couplings? 
What   is  the   difference   between   an  air  brake   and   an   air 
•signal  coupling? 

A.  So  no  dirt  or  foreign  matter  will  get  into  the  open 
coupling  and  work  into  the  triple  or  brake  valve  or  stop 
up  strainers.  So  couplings  and  gaskets  will  not  get  injured 
or  broken  dragging  over  rails  and  crossings.  If  blown 
out  each  time,  any  water,  sand  or  dirt  in  the  tender  piping 
will  be  blown  out.  Air  brake  and  air  signal  couplings  are 
of  different  sizes — made  so  purposely — so  the  brake  line 
cannot  be  coupled  to  the  signal  line.  The  opening  and  lip 


TESTING     FOR     LEAKS  51 

of  the  lock  iii  brake  coupling  is  much  wider  than  the  signal 
coupling,  so  the  brake  coupling  will  not  go  into  it.  It  is 
the  practice  to  paint  the  signal  couplings  red  so  they  are 
more  easily  distinguished  when  taking  hold  of  them  to 
couple  up. 

7.  Q.     If  main  reservoir  has  water  in  it,  how  will  it 
affect   the   operation    of   the   brake? 

A.  The  water  in  main  reservoir  reduces  the  supply  of 
air  stored  there  in  proportion  to  the  amount  of  water  con- 
tained. The  brake  will  set  the  same,  but  on  a  long  train 
will  not  release  as  readily,  as  there  will  not  be  enough  air 
stored  to  recharge  the  brake  pipe  quickly  and  you  must 
wait  to  have  it  pumped.  The  main  reservoir  should  be 
entirely  clear  of  water,  even  if  it  is  necessary  to  drain  it 
each  trip,  so  as  to  get  a  prompt  release  and  recharging 
of  train. 

8.  Q.     How  does  this  water  get  into  the  main  reserv- 
voir? 

A.  The  air  from  the  atmosphere  before  compression 
contains  more  or  less  moisture  in  the  shape  of  vapor. 
After  compression  the  air  can  not  hold  all  this  vapor  as  it 
is  compressed  to  a  very  much  smaller  volume,  so  nearly  all 
the  vapor  falls  to  the  bottom  of  the  main  reservoir  as  solid 
\vater  as  soon  as  the  air  cools  off  to  the  normal  tempera- 
ture of  the  outside  air.  If  the  pump  runs  hot  so  the  air 
does  not  cool  off  in  the  main  reservoir  some  of  the  water 
will  be  found  in  the  triple  valves  and  drain  cups. 

9.  Q.     Of  what  use  is  the  extra  main  reservoir'  press- 
ure,  and  does   the  size  of  the   reservoir  have  anything  to 
do  with  the  amount  of  excess  pressure  you  carry? 

A.  It  recharges  the  brake  pipe  and  forces  the  triple 
pistons  up  into  exhaust  position  quicker  and  surer,  so 
that  all  brakes  release  about  the  same  instant;  recharges 
the  auxiliary  to  full  pressure  in  less  time,  ready  for  the 
next  application.  With  a  large  main  reservoir  there  is  a 
greater  volume  of  compressed  air  stored  to  draw  from, 
so  a  less  number  of  pounds  of  excess  pressure  will  do  the 
work  than  with  a  small  reservoir.  With  a  short  train 


52  EXCESS  PRESSURE 

good  work  can  be  done  with  less  excess  than  on  a  long 
train.  Excess  pressure,  as  well  as  a  large  volume  of 
stored  air,  is  needed  on  a  long  train,  so  the  air  will  travel 
from  the  engine  to  the  rear  car  more  quickly  and  release 
the  rear  brakes  at  nearly  the  same  instant  the  front  ones 
release;  this  will  avoid  many  break-in-twos.  Excess  is 
needed  to  release  brakes  and  large  volume  to  hold  up  the 
pressure  in  brake  pipe  for  recharging.  The  main  reser- 
voir should  always  be  drained  of  water  so  it  will  be  full 
sized. 

10.  Q.     Could    it    release    the    brakes    with    an    empty 
brake  pipe  as  readily  as  when  the  pressure  in  the  brake 
pipe  had  been  reduced  only  20  or  25  pounds?     Why? 

A.  No.  When  the  air  from  the  main  reservoir  ex- 
pands into  an  empty  brake  pipe,  it  will  not  fill  it  up  and 
equalize  at  as  high  a  pressure  as  when  the  brake  pipe  has 
some  compressed  air  left  in  it.  For  instance,  the  brake 
pipe  line  of  25  freight  cars  holds  16,000  cubic  inches, 
about  as  many  cubic  inches  of  air  as  an  ordinary  main 
reservoir.  If  this  brake  pipe  is  entirely  empty  and  the 
main  reservoir  has  90  pounds,  it  will  equalize  into  twice 
the  space,  and  show  half  the  pressure,  or  45  pounds  in 
each.  The  brake  would  be  set  at  50  pounds;  with  that 
pressure  above  triple  piston,  brakes  could  not  release  until 
the  pump  had  raised  the  pressure  over  five  pounds.  Now, 
if  the  brake  pipe  line  has  been  reduced  25  pounds,  having 
45  pounds  still  left  in  it,  90  in  main  reservoir  and  45  in 
brake  pipe,  would  equalize  at  a  little  over  65,  which  would 
raise  triple  pistons  so  brakes  would  release  promptly. 

11.  Q.     Would  you  run  your  pump  as  fast  to  recharge 
an  empty  brake  pipe  as  one  with  45  or  50  pounds  in  it? 
Is  there  any  economy  in  retaining  as  much  air  as  possible 
and  keeping  the  pump  cool? 

A.  The  pump  would  have  to  run  faster  to  recharge  an 
empty  brake  pipe  than  one  with  45  or  50  pounds  in  it. 
When  you  empty  the  brake  pipe  of  25  cars  it  wastes  as 
much  air  as  when  you  empty  a  small  main  reservoir; 
smaller  trains  in  proportion.  This  would  make  some 


EXCESS    PRESSURE  53 

pumps  hot  to  supply.    Always  save  your  air  and  keep  the 
pump  cool,  no  matter  what  length  of  train  you  handle. 

12.  Q.     Please   explain   what   excess   pressure   is. 

A.  Excess  pressure  is  the  difference  between  the  main 
reservoir  and  brake  pipe  pressures  when  the  brake  valve  is 
in  running  position  so  that  the  excess  valve  or  the  feed 
valve  can  maintain  a  difference  between  the  two  press- 
ures. In  full  release  position  these  valves  are  cut  out, 
but  the  air  can  pass  through  an  open  port  from  the  main 
reservoir  to  the  brake  pipe  and  equalize,  so  in  release 
position  there  is  no  excess.  If  you  carry  excess  you  aim 
to  prevent  this  equalization  and  thus  have  a  greater 
amount  of  air  in  main  reservoir  to  equalize  into  brake 
pipe  when  necessary  to  release  brakes.  Of  course  it  takes 
more  excess  to  promptly  release  all  the  brakes  on  a  long 
train  than  a  short  one.  When  releasing  brake,  it  supplies 
the  brake  pipe  with  a  higher  pressure  than  brake  was  first 
set  at;  this  makes  the  movement  of  all  triples  to  release 
position  much  quicker  and  surer.  With  a  long  train  it  is 
absolutely  necessary  for  this  purpose.  On  a  long  train 
excess  is  needed  to  force  the  air  back  through  brake  pipe 
quickly  and  release  brakes,  with  large  volume  to  hold  the 
pressure  up.  It  recharges  the  auxiliaries  quicker,  ready 
for  the  next  application  of  the  brake.  It  charges  empty 
cars  quicker  that  are  taken  on  the  train.  When  brakes 
"creep  on,"  they  can  be  released  at  once  by  placing  the 
brake  valve  on  full  release  for  a  second  or  two,  just 
long  enough  to  raise  the  triple  to  exhaust  position  and 
not  long  enough  to  charge  the  reservoirs  to  a  higher  press- 
ure, then  returning  it  to  running  position. 

13.  Q.     Have  we  more  than  one  pattern  of  equalizing 
discharge  brake  valve? 

A.  Yes,  we  have  several  kinds  of  them  in  service, 
called  E-6,  or  F-6,  D-8,  H-5,  and-  H-6,  from  the  number 
of  the  plate  on  which  each  is  illustrated  in  the  Westing- 
house  catalogue.  The  E-6  and  F-6  valves  are  exactly 
alike  and  are  now  known  as  the  "1892  model"  or  F-6 
valve.  Very  few  of  the  D-8  valves  are  now  in  service. 


54  THE    BRAKE     VALVE 

The  H-5  and  H-6  brake  valves  came  next  after  the  F-6 
or  1892  model,  and  may  be  styled  the  1906  model. 

14.  Q.  Describe  the  principle  on  which  it  operates 
and  what  difference  there  is  between  the  patterns. 

A.  This  brake  valve  has  a  rotary  valve  with  various 
ports  and  cavities  in  it  by  which  the  air  can  pass  to  and 
from  the  various  pipes  and  connections  when  the  engineer 
moves  the  rotary.  It  also  has  a  piston  in  it  called  the 
equalizing  piston,  with  a  brake  pipe  exhaust  valve  on  the 
bottom  side  of  it  which  is  designed  to  automatically  re- 
duce the  brake  pipe  pressure.  When  brake  valve  is  not 
being  operated  this  piston  has  an  equal  pressure  on  both 
sides  of  it,  so  it  remains  stationary,  holding  brake  pipe 
exhaust  valve  closed.  When  it  is  used  to  set  the  brake, 
the  reduction  of  air  pressure  is  not  made  by  the  engineer 
direct  from  the  brake  pipe,  but  from  the  chamber  in  the 
valve  over  the  equalizing  piston  and  the  small  reservoir 
connected  to  the  chamber.  If  the  engineer  wishes  to  re- 
duce the  brake  pipe  pressure  any  specified  amount — say 
seven  pounds — he  moves  the  rotary  to  service  application 
position.  As  the  rotary  passes  lap  position,  the  ports 
which  allow  the  air  to  pass  from  one  part  of  the  brake 
valve  to  another  are  all  closed.  The  main  reservoir  air 
is  held  on  top  of  the  rotary  as  it  is  not  used  when  the 
brake  is  set,  but  only  when  releasing  or  charging  the 
brake  pipe  and  auxiliary  reservoirs.  The  air  above  the 
equalizing  piston  and  the  brake  valve  reservoir  being  cut 
off  from  all  other  air  may  be  called  brake  valve  air,  it  is 
what  operates  the  automatic  part  of  the  brake  valve  to 
equalize  the  discharge  of  the  brake  pipe  air,  which  is 
below  the  piston.  When  the  pressure  of  the  brake  valve 
air  is  reduced  by  allowing  some  of  it  to  escape  from  the 
preliminary  exhaust  port,  it  does  not  reduce  the  brake 
pipe  air  through  the  same  opening;  so  the  equalizing 
piston  having  less  pressure  above  it,  raises  up,  opening 
the  brake  pipe  exhaust  valve  on  the  bottom  of  this  piston 
and  air  flows  out  of  the  brake  pipe.  As  soon  as  the  brake 
valve  air  is  reduced  the  amount  the  engineer  wishes  (and 


THE    BRAKE   VALVE 


5.5 


the  amount  of  the  reduction  is  shown  with  the  black  hand 
of  gage)  he  closes  the  preliminary  exhaust  port  by  a 
movement  of  the  rotary  to  lap.  The  pressure  of  the  brake 
valve  air  then  remains  stationary;  while  the  brake  pipe 
air  flows  out  through  the  brake  pipe  exhaust  till  it  is 
reduced  a  little  lower  than  the  brake  valve  air,  which  then 
moves  the  piston  down  gradually  and  closes  the  brake  pipe 

EQUALIZING  DISCHARGE  VALVE 

WITH  FEED  VALVE  ATTACHMENT. 

1892  MODEL. 


&MKE  MLVE 

Running 


PLATE  D  5    PLATE  E'6. 
and    PLATE  F6. 

These  Broke  Yalrcs  arc 
^cillhe  in  construction 
ano/opercrf/on. 


FEED  VALVB 


exhaust.  It  takes  longer  to  reduce  pressure  in  a  long 
brake  pipe  than  in  a  short  one  through  the  small  brake 
pipe  exhaust  port  because  of  the  greater  volume  of  air  in 


56 


THE    BRAKE   VALVE 


the  long  pipe,  so  the  brake  pipe  exhaust  is  held  open  by 
the  brake  pipe  air  till  the  pressure  is  reduced  the  whole 
length,  then  closed  automatically  by  the  pressure  of  the 
brake  valve  air. 

Each  of  these  valves  uses  a  double  hand  gage  and  has 
a  small  reservoir  about  12  inches  long  connected  to  it  by 


COVCWOR  ft  GAUCT 

-RED  HANO- 

MAM  RtscK 


a  small  pipe;  this  equalizing  reservoir  is  used  to  supply 
the  cavity  over  equalizing  piston  with  a  larger  volume  of 
air,  so  a  more  gradual  reduction  of  pressure  can  be  made 
through  the  preliminary  exhaust  port  from  this  cavity. 
The  later  size  of  this  reservoir  is  145/£  inches  long;  it  con- 
tains a  larger  volume  of  air  than  those  first  used  and 
thus  makes  the  reduction  of  brake  valve  air  more  gradual. 
The  F-6  has  a  reducing  or  feed  valve  attached,  which 
is  set  to  regulate  the  brake  pipe  pressure  at  not  over  70 
pounds,  at  which  pressure  it  closes  and  no  more  air  can 
pass  to  brake  pipe  from  main  reservoir  till  the  brake  pipe 
pressure  falls  below  what  the  feed  valve  is  set  at,  when  it 


THE    FEED    VALVE  57 

opens  again;  with  this  valve  the  governor  is  piped  to  main 
reservoir  and  set  at  ninety  pounds. 

Either  of  these  valves  when  placed  on  emergency 
position  opens  a  large  port  which  lets  the  air  from  the 
brake  pipe  direct  to  the  atmosphere,  making  a  sudden 
reduction,  which  causes  the  brake  to  go  on  suddenly  and 
with  full  force. 

15.  Q.  Describe  the  feed  valve  or  brake  pipe  pressure 
regulator.  How  many  kinds  are  in  use  and  what  are  the 
differences  in  their  operation? 

A.  There  are  three  forms  of  the  feed  valve  in  general 
use.  The  older  one,  called  F-6,  has  a  poppet  valve,  63, 
which  is  opened  and  closed  by  -the  movement  of  a  piston, 
74,  which  piston  is  moved  in  one  direction,  down,  by  the 
pressure  of  the  brake  pipe  air,  and  up  by  a  regulating 
spring,  68. 

When  the  feed  valve  63  is  open,  as  shown  in  the  illus- 
tration, the  main  reservoir  air  which  comes  from  the 
brake  valve  when  in  running  position,  comes  through  /, 
passes  by  valve  63  into  cavity  B,  as  shown  by  the  arrow, 
and  out  through  port  i  into  the  brake  pipe.  Piston  74  is 
held  up  against  the  brake  pipe  pressure  in  B  by  the  regu- 
lating spring  68,  which  is  adjusted  to  hold  the  piston  up 
so  the  supply  valve  will  not  close  till  the  pressure  reaches 
the  standard  amount,  usually  seventy  pounds;  at  which 
pressure  the  piston  is  moved  down  far  enough  to  allow 
valve  63  to  close  on  its  seat  and  shut  off  the  supply  of 
main  reservoir  air  passing  into  the  brake  pipe. 

If  from  any  cause  the  brake  pipe  pressure  is  reduced 
below  the  standard  amount,  the  regulating  spring  pushes 
the  piston  and  valve  63  up,  so  that  air  passes  from  the 
main  reservoir  to  the  brake  pipe.  This  action  of  the  feed 
valve  maintains  the  pressure  in  the  brake  pipe  at  the 
standard  amount  steadily,  provided  there  is  enough  in  the 
main  reservoir. 

The  brake  pipe  pressure  begins  to  move  the  piston 
down  against  the  stiffness  of  the  regulating  spring  at  about 
forty-five  pounds,  so  that  valve  63  begins  to  close  a  little 


58 


F-6    FEED   VALVE 


at  that  pressure.  As  the  pressure' increases  it  compresses 
the  spring  more,  until  at  seventy  pounds  piston  74  is  down 
so  the  valve  63  has  entirely  closed.  On  account  of  this 

PLATE     F.G 


FEED   VALVE   OPEN  /=F£O  VfJLY£ CLOSED 

action  of  the  F-6  feed  valve  the  passage  of  air  from  the 
main  reservoir  to  the  brake  pipe  was  free  up  to  forty- 
five  or  fifty  pounds,  and  was  then  gradually  restricted  as 
the  pressure  raised,  so  that  between  sixty-five  and  seventy 
pounds  the  opening  was  so  small  that  with  a  long  train 
or  much  leakage  it  took  a  long  time  to  feed  up  between 
those  pressures. 

To  stop  the  piston  in  case  the  brake  valve  is  in  full 
release  position,  the  lower  part  of  the  piston  comes  against 
the  top  part  of  the  spring  case  69,  in  the  illustration  the 
piston  is  shown  in  this  position,  in  service  it  moves  down 
only  far  enough  to  allow  valve  63  to  close.  The  small 


F-6    FEED    VALVE    DEFECTS  59 

spring  64  closes   the  valve  when  the  piston  moves   down. 

The  two  gaskets  72  are  intended  to  stop  any  brake 
pipe  air  leaking  by  the  piston.  There  is  a  recess  in  bush- 
ing ring  75  deep  enough  to  hold  the  smaller  gasket  when 
the  piston  is  down.  If  this  gasket  is '  too  thick  for  this 
recess  it  will  hold  up  piston  and  feed  valve  so  that  brake 
pipe  pressure  will  get  too  high.  If  spring  case  69  is 
screwed  up  too  far  into  valve  body  62,  the  edge  of  the 
larger  gasket  will  be  smashed  out  thin,  the  two  gaskets 
will  then  fill  the  recess  in  75  and  hold  the  piston  up  and 
valve  63  open,  which  will  allow  brake  pipe  pressure  to' 
feed  up  too  high. 

If  the  stem  of  valve  63  that  runs  up  into  the  cap  nut 
65  gets  bent,  the  valve  will  not  seat  squarely,  and  air  will 
leak  past  it  steadily. 

A  leak  through  the  gasket  56  from  port  f  to  port  i  will 
allow  air  to  pass  from  the  main  reservoir  to  brake  pipe 
without  passing  valve  63. 

Do  not  confound  this  leak  with  a  leak  through  gasket 
61  in  the  brake  valve,  which  allows  the  air  from  main 
reservoir  to  flow  into  chamber  D  in  any  position  except 
full  release.  A  leak  through  the  feed  valve  affects  the 
pressures  in  running  position  only,  as  that  is  the  only 
position  in  which  air  can  pass  the  rotary  to  the  feed  valve. 

The  feed  valve  attachment  must  be  kept  clean  if  it  is 
expected  to  work  correctly.  If  the  valve  63  gets  gummy 
so  that  it  is  not  air  tight  on  its  seat,  the  main  reservoir 
will  tend  to  equalize  with  the  brake  pipe  at  more  than  the 
standard  amount. 

The  Slide  Valve  Feed  Valve,  G-6,  which  is  a  later  type 
than  the  F-6,  is  shown  in  two  positions,  has  a  slide  valve 
55,  to  open  and  close  the  air  supply  port  b,  and  allow  air 
to  pass  from  the  main  reservoir  to  the  brake  pipe  when 
the  rotary  is  in  running  position.  This  supply  valve  is 
operated  by  a  piston,  54,  which  is  moved  in  one  direction 
by  the  main  reservoir  air  pressure,  in  the  other  by  a 
spring,  58. 

To  aid  the  reader  we  have  prepared  two  sketches  of 


G-6   FEED  VALVE 


this  feed  valve  in  which  the  parts  and  passages  are  shown 
in  such  relations  to  each  other  that  the  flow  of  air  through 
the  complete  valve  may  be  more  easily  understood. 

With  the  G-6  feed  valve  the  pressure  of  the  main 
reservoir  air  against  the  piston,  54,  must  be  sufficient  to 
push  it  over  against  the  strength  of  the  spring  58,  before 
the  slide  valve  will  be  moved  to  uncover  port  b.  With 
this  valve  at  work  feeding  up  the  brake  pipe  the  main 
reservoir  will  show  slight  excess  pressure  at  all  times. 
This  you  do  not  see  with  the  F-6  valve,  as  its  feed  valve 
is  not  held  open  by  the  main  reservoir  pressure. 

Main  reservoir  air  enters  at  f,  passes  into  the  slide 
valve  chamber  F  on  top  of,  around  the  ends  and  sides  of 


SUIDE 


/AI/VJE  FEEO  VA.LVE. 

^CLOSED    POSITION 

S5      *«     58 


Fig.   4. 


valve  55  and  against  piston  54.  Chamber  E,  on  the  other 
side  of  the  piston,  is  connected  through  passage  c  with  the 
chamber  around  regulating  valve  59,  and  if  this  valve  is 
open,  air  from  E  will  pass  through  a  into  the  brake  pipe 


G-6   FEED   VALVE  61 

through  i,  so  that  air  in  E  can  equalize  with  that  in  the 
brake  pipe. 

A  diaphram,  57,  which  consists  of  two  thin  brass  sheets 
keeps  the  brake  pipe  air  from  escaping  to  -the  atmosphere 
through  the  spring  case,  this  diaphram  rests  on  a  piston, 
64,  which  is  held  up  by  the  regulating  spring  67.  The 
stern  of  the  regulating  valve  59,  rests  against  this  dia- 
phram, when  57  moves  over,  the  regulating  valve  moves 
with  it.  With  reservoir  pressure  in  F  and  brake  pipe 
pressure  in  E,  the  piston  and  slide  valve  moves  from  the 
position  shown  in  Fig.  4  to  that  shown  in  Fig.  3,  so  that 
the  port  is  open  at  b,  allowing  air  to  pass  from  /  to  i. 
Piston  54  is  not  a  tight  fit  in  its  bushing,  while  the  main 
reservoir  pressure  is  holding  it  over  against  the  spring 
58,  air  is  leaking  by  the  piston  steadily  from  F  into  E  and 
thence  through  passage  c,  past  the  regulating  valve  and 
passage  a  into  the  brake  pipe;  in  addition  to  what  goes 
in  at  port  b  so  that  air  is  feeding  into  the  brake  pipe 
through  two  passages  b  and  c. 

When  brake  pipe  pressure  reaches  the  standard  amount 
it  has  moved  the  diaphram  and  its  piston  over  against  the 
resistance  of  spring  67  and  allowed  valve  59  to  seat  as 
shown  in  Fig  4.  This  stops  the  passage  of  air  from  E 
to  brake  pipe,  piston  54  not  being  an  air  tight  fit,  air 
from  F  soon  equalizes  with  E.  Spring  58,  which  was 
compressed  when  the  piston  moved  towards  E,  now 
reacts,  pushes  54  and  55  back  into  position  shown  in  Fig. 
4,  this  stops  the  flow  of  air  through  b  into  the  brake  pipe, 
as  the  regulating  valve  has  stopped  the  flow  of  air  from 
E,  no  more  air  passes  in  at  either  place,  and  brake  pipe 
pressure  will  not  rise  any  higher.  When  brake  pipe 
pressure  falls  below  the  standard  amount,  the  regulating 
spring  will  move  the  piston  64  and  diaphram  enough  to 
unseat  valve  59,  air  in  E  can  then  equalize  with  brake  pipe, 
reservoir  pressure  in  F  at  once  moves  the  piston  and  slide 
valve  as  shown  in  Fig.  3  and  air  feeds  into  brake  pipe 
again. 

If  the  regulating  valve  leaks,  if  either  of  the  cap  nuts 


€2 


B-6    FEED   VALVE 


53  or  61  leak,  or  if  the  spring  58  is  too  weak,  or  gone,  the 
piston  will  hold  slide  valve  open  so  that  brake  pipe  press- 
ure may  get  too  high.  If  the  opening  by  the  seat  of  the 
regulating  valve  is  stopped  up,  or  the  regulating  spring  is 
too  weak,  the  -slide  valve  will  be  closed.  To  clean  valve 
59  leave  rotary  in  service  position  and  take  off  cap  nut  61. 
To  clean  piston  54  remove  cap  nut  53.  Piston  54  has  no 
packing  rings,  it  should  be  clean  and  free  from  gum. 

If  the  feed  valve  is  dirty  and  gummed  up  it  will  act 
so  slowly  that  the  head  brakes  are  apt  to  creep  on  when 
you  go'  to  running  position  after  a  release. 

The  B-6  feed  valve  is  much  the  same  as  the  G-6,  the 
first  ones  B-4  had  a  small  port  drilled  through  the  piston 
8  and  a  packing  ring  9,  that  regulates  the  supply  of  main 
reservoir  air  passing  into  the  chamber  G  behind  the 
piston.  The  later  valves  B-6  do  not  have  this  air  port 
and  packing  ring.  In  all  respects  the  operation  of  the 
piston  with  its  supply  valve,  and  the  regulating  valve  is 
the  same  as  the  G-6  feed  valve.  But  there  is  a  quick 


DIAGRAM  OF  B-6  FEED  VALVE,  CLOSED 


DIAGRAM  OF  B-6  FEED  VALVE,  OPEN 


thread  screw  on  the  regulating  nut  23  that  allows  a  change 
to  be  made  in  the  tension  of  the  regulating  spring  18  so 
that  the  pressure  of  the  brake  pipe  air  can  be  changed 


REGULATING    THE    FEED    VALVE  63 

from  70  to  110  pounds,  or  vice  versa,  by  a  partial  revolu- 
tion of  the  small  hand  wheel  that  is  part  of  the  regulating 
nut  23.  Secured  to  the  spring  case  19  are  two  split  rings. 

20  and  21,  a  small  screw  22  binds  the  ends  of  the  split 
ring  when  once  adjusted  so  it  cannot  slip  around  on  the 
spring  case  19.     The  feed  valve  is  first  adjusted  to  close 
at  the  lower  pressure,  say  70  pounds,  and  the  split  ring 

21  brought   against  the  pin  fixed   in   the   hand   wheel   23. 
The  wheel  and  adjusting  nut  23   are  now  turned  to   in- 
crease the  tension  on  the  spring  18  till  the  valve  will  close 
at  the  higher  pressure,  say  110  pounds,  and  the  split  ring 

22  is  moved  against  the  other  side  of  the  pin  in  23.     By 
turning  23  so  the  pin  rests  against  one  or  the  other  of 
the  stops  on  the  rings  21  or  22,  the  tension  of  the  spring 
is  adjusted  for  the  proper  pressures.     This  type  of  feed 
valve  is  usually  attached  to  a  pipe  bracket,  as  shown  in 
the  cut,  but  it  can  be  attached  to  the  1892  model  valve  the 
same  as  the  G-6   feed  valve.     When  so  used  it  will   do 
away  with  the  pipe  bracket,  the  reversing  cock  and  one  of 
the  two  G-6  feed  valves  used  with  the  high  speed  brake. 

16.  Q.     What    pressure    does    the    black    hand    of    the 
double  gage  show,  and  why? 

A.  It  shows  the  pressure  in  chamber  D  above  the 
equalizing  piston  in  the  brake  valve,  and  in  the  brake 
valve  reservoir,  it  is  connected  to  the  pipe  from  chamber 
D  to  the  small  reservoir  and  not  to  the  brake  pipe.  It  is 
connected  in  this  manner  because  wherf  applying  the 
brake  the  engineer  must  know  exactly  how  much  he  re- 
duces the  brake  valve  pressure  over  the  equalizing  piston, 
therefore  the  black  hand  must  show  the  exact  pressure 
there  while  making  a  service  reduction.  If  the  brake  is 
set  with  a  direct  or  emergency  application  the  gage  does 
not  at  once  show  the  exact  brake  pipe  reduction. 

17.  Q.     In  what  position   of  brake  valve  does   it  also 
show  the  exact  brake  pipe  pressure? 

A.  Full  release,  running  position,  or  anywhere  between 
full  release  and  lap.  In  these  positions  the  equalizing 
port  g  which  is  the  communication  between  the  brake  pipe 


64  BLACK    HAND    PRESSURE 

and  the  chamber  D,  is  open.  In  any  other  position  this 
port  is  shut  to  the  brake  pipe  pressure  so  it  is  not  con- 
nected to  the  black  hand  direct. 

18.  Q.     Then  the  black  hand  does  not  show  the  exact 
brake  pipe  pressure  when  on  lap  or  past  lap  towards  the 
emergency  position  ? 

A.  No,  not  immediately,  and  you  can  easily  prove 
this  by  placing  the  valve  on  lap  and  opening  the  angle 
cock  at  rear  end  of  tender;  the  brake  pipe  pressure  will 
drop  to  nothing  at  once,  which  the  black  hand  will  not 
do.  Usually  the  equalizing  piston  packing  ring  leaks  a 
little,  and  the  black  hand  will  drop  back  slowly  as  the  air 
leaks  out  into  the  empty  brake  pipe;  if  there  are  no  leaks 
in  the  brake  valve,  or  connections  to  gage  or  brake  valve 
reservoir,  it  will  not  drop  any.  Unless  the  packing  ring 
leaks  considerable  it  does  little  harm.  A  very  small  leak 
is  an  advantage  as  it  will  show  on  the  black  hand  the 
brake  pipe  pressure  as  soon  as  the  pressures  can  equalize 
past  the  piston,  it  can  warn  the  engineer  if  valve  is  left 
on  lap  and  brake  pipe  pressure  falls  slowly  without  setting 
the  brake. 

If  the  air  in  the  brake  pipe  and  chamber  D  can  equalize 
past  piston  47  the  black  hand  will  show  brake  pipe  press- 
ure; when  auxiliaries  have  equalized  with  brake  pipe,  it 
will  show  both  pressures. 

19.  Q.    When  the  brake  valve  has  been  left  on  release 
position  till  brake  pipe  and  main  reservoir  have  equalized 
at  seventy  pounds,  and  is  then  placed  on  running  position, 
are  the  brakes  apt  to  creep  on  at  once?    Why  is  this? 

A.  When  the  valve  is  placed  on  running  position,  it 
shuts  off  the  air  from  brake  pipe  till  the  excess  pressure 
is  picked  up  in  the  main  reservoir  to  force  the  air  past 
feed  valve;  before  this  excess  is  picked  up  if  the  brake 
pipe  leaks,  the  brake  will  set.  In  such  a  case,  run  your 
pump  a  little  faster  for  a  few  minutes — not  over  five — 
so  as  to  get  the  excess  quicker.  If  train  is  under  motion 
and  you  feel  a  brake  dragging,  put  the  brake  valve  in  full 
release  for  a  second  only,  then  place  it  in  running  posi- 


BRAKE     VALVE     POSITIONS  65 

tion;  this  may  have  to  be  done  a  second  or  third  time 
until  air  begins  to  go  through  feed  valve,  when  it  will 
hold  brakes  off.  A  short  rule  for  this  is:  Keep  your 
excess  all  the  time  by  not  using  the  full  release  position, 
except  at  the  time  of  releasing  the  brakes,  then  running 
position  will  hold  them  off. 

20.  Q.  Please  state  the  different  positions  of  the  brake 
valve,  the  course  the  air  takes  passing  through  it,  and 
what  ports  are  covered  in  each  position. 

NOTE — To  aid  the  student  we  have  prepared  some 
sketches  of  the  D-8  brake  valve  that  form  its  construc- 
tion and  is  more  easily  explained  than  the  later  valves,  in 
which  the  rotary  13  is  shown  as  if  it  were  a  long  valve 
sliding  in  a  straight  line  back  and  forth  over  a  valve  seat 
instead  of  turning  on  a  center  as  the  actual  rotary  valve 
really  does.  In  these  sketches  the  rotary  is  shown  as  if 
cut  between  the  .preliminary  exhaust  cavity  p  and  the 
emergency  exhaust  cavity  and  straightened  out  as  a  hoop 
is  straightened  out  when  cut  across.  The  ports  are  shown 
in  somewhat  changed  positions  so  they  will  be  in  proper 
communication  with  the  ports  and  cavities  in  the  sliding 
valve  13.  Ports  a  and  g  are  shown  in  the  sketch  as  if 
they  communicated  with  each  other,  in  the  actual  rotary 
valve  a  is  nearer  the  center  than  g,  so  in  service  they  do 
not  register  with  each  other.  In  actual  service  port  / 
registers  with  f  in  running  position  as  shown,  and  with 
port  g  in  emergency  position;  but  for  the  purposes  of  ex- 
planation the  sketch  gives  a  very  good  idea  of  the  course 
of  the  air  in  the  various  positions  of  the  D-8  valve. 

A.  When  on  full  release  position,  main  reservoir  air 
which  comes  in  the  brake  valve  on  top  of  the  rotary  can 
pass  through  opening  a  in  the  rotary  into  a  cavity  in 
the  rotary  valve  seat  b  and  from  there  around  the  bridge 
in  rotary  and  into  the  brake  pipe  direct;  in  this  position 
the  main  reservoir  and  brake  pipe  pressures  can  equalize. 
The  air  from  main  reservoir  also  passes  through  the  feed 
port  /  in  rotary  valve  into  the  supply  port  e  for  the  pre- 
liminary exhaust  and  down  into  chamber  D.  Air  can  also 


FULL 


DIAGRAMMATIC    BRAKE    VALVE 


67 


pass  into  chamber  D  from  the  brake  pipe  cavity  c  in  rotary 
valve  through  equalizing  port  g.  In  this  position  the 
warning  port  is  open  so  main  reservoir  air  blows  through 
rotary  into  main  exhaust  port.  The  preliminary  exhaust 
and  emergency  exhaust  ports  are  closed  as  well  as  the  feed 
port  f  leading  to  the  excess  valve  or  feed  valve. 

When  on  the  next  position,  called  running  position 
because  it  is  the  proper  position  when  train  is  running 
with  brakes  released,  the  direct  supply  port  is  covered  so 
that  main  reservoir  air  can  not  get  into  brake  pipe  direct, 
the  supply  port  e  is  also  covered  so  no  main  reservoir  air 
can  pass  through  into  chmber  D.  The  feed  port  f  is 
opened  and  main  reservoir  air  must  then  pass  through  this 
port  and  go  past  the  excess  valve  or  feed  to  get  into  the 
brake  pipe.  Brake  pipe  air  can  pass  through  the  cavity 
c  under  rotary  and  go  through  port  g  into  chamber  D  and 
equalize  the  pressure  on  both  sides  of  the  equalizing 
piston.  The  small  warning  port  is  covered.  On  lap  posi- 


tion all  ports  are  closed  so  no  air  can  pass  under  or 
through  the  rotary.  On  service  application  position  the 
preliminary  exhaust  port  h  is  opened  so  air  flows  out  of 
chamber  D ;  this  is  done  by  a  movement  of  the  rotary,  the 
equalizing  piston  opens  the  brake  pipe  exhaust  port  auto- 
matically. All  other  ports  are  closed. 

On   emergency  position   the   direct  application   port   is 
opened,  allowing  the  air  in  the  brake  pipe  to  pass  directly 


£M URGENCY      F>OS/T/0/V 


LEAKS  69 

to  the  atmosphere  through  the  cavity  under  the  rotary. 
As  this  is  the  largest  port  in  the  brake  valve,  if  it  is  opened 
wide  the  air  in  the  brake  pipe  will  escape  suddenly. 

The  preliminary  exhaust  port  is  left  open,  all  other 
ports  are  closed.  The  port  from  brake  valve  to  brake 
valve  reservoir  is  open  at  all  times. 

21.  Q.     Do  leaks  in  the  brake  valve  interfere  with  its 
work? 

A.  Yes;  if  there  is  a  leak  under  the  rotary  valve  from 
the  main  reservoir  to  brake  pipe,  the  brake  pipe  pressure 
will  raise  so  that  the  brake  will  release  when  valve  is  on 
lap.  A  leak  from  brake  pipe  under  rotary  valve,  or 
through  brake  pipe  discharge  valve  to  atmosphere,  or  a 
leak  between  equalizing  reservoir  and  brake  valve  when 
valve  is  on  lap,  will  set  the  brake  tighter  than  you  want 
it.  If  it  leaks  through  gasket  from  main  reservoir  to 
cavity  over  equalizing  piston  47  in  F-6  valve,  or  past 
gasket  18  in  the  H-type  valve,  brake  cannot  be  set  in 
service  application,  as  air  will  flow  into  chamber  D  from 
main  reservoir  as  fast  as  it  flows  out  of  preliminary 
exhaust.  Using  the  brake  valve  on  emergency  habitually 
will  tend  to  cut  the  rotary  and  seat  quicker,  as  it  brings 
sand  and  scales  of  iron  rust  up  from  the  brake  pipe  on 
the  seat,  which  the  service  application  will  not  do.  If 
the  brake  valve  is  fastened  close  to  the  boiler  head  so  it 
gets  very  hot,  the  leather  gaskets  get  burned  and  crack 
so  they  leak  badly.  A  bad  leak  past  the  equalizing  piston 
will  cause  engine  brakes  to  release  when  set  with  a  light 
direct  application.  .This  is  because  air  leaks  from  equal- 
izing reservoir  past  piston  and  raises  brake  pipe  pressure 
in  the  short  brake  pipe  on  engine  and  tender.  This  leak 
will  also  prevent  the  equalizing  piston  raising  when  mak- 
ing a  service  reduction  if  the  air  can  come  past  the  piston 
into  chamber  D  as  fast  as  it  is  discharged  through  pre- 
liminary exhaust  port.  It  also  makes  the  brake  pipe  re- 
duction less  than  the  gage  at  first  shows.,  on  a  long  train. 

22.  Q.     What  is  the  effect  if  equalizing  reservoir  pipe 
is  broken  so  a  blind  joint  has  to  be  made? 


70  BROKEN     EQUALIZING     RESERVOIR     PIPE 

A.  The  brake  cannot  be  set  with  a  gradual  application 
in  service  position;  there  is  so  little  air  above  the  equal- 
izing piston,  it  escapes  out  of  preliminary  exhaust  so 
quickly  that  the  pressure  above  piston  is  reduced  more 
than  twenty  pounds,  equalizing  piston  stays  up  and  the 
brake  works  with  full  application;  some  times  emergency 
with  a  very  short  train. 

23.  Q.     What  should  you  do  in  such  a  case? 

A.  If  joints  cannot  be  made  so  as  to  use  equalizing 
reservoir  again,  a  blind  joint  should  be  made  at  its  con- 
nection "with  brake  valve;  the  elbow  in  brake  pipe  exhaust 
should  be  plugged  and  valve  used  with  direct  application 
port,  taking  care  to  make  a  gradual  reduction  so  brake 
will  not  go  on  with  emergency,  and  closing  valve  slowly 
so  the  brakes  on  head  end  will  not  be  kicked  off.  The 
elbow  has  a  thread  cut  in  it  for  plugging;  if  it  is  not 
threaded  take  it  out  and  plug  the  hole  with  the  plug  in 
the  equalizing  reservoir.  A  $i  plug  is  used  with  the 
type  H  valve. 

24.  Q.     With  the  equalizing  discharge  valve,  why  does 
the  air  blow  out  of  the  brake  pipe  exhaust  when  brake  is 
released,    if  working   brake   on   engine   and   tender   only? 

A.  Because  the  brake  pipe  is  charged  up  through  a 
large  hole  in  rotary  valve;  the  cavity  over  equalizing 
piston  and  brake  valve  reservoir  is  charged  from  the  main 
reservoir  through  the  small  supply  port  e  for  preliminary 
-exhaust,  and  by  equalizing  port  g.  If  the  brake  pipe  is 
-short,  it  will  charge  up  to  a  full  pressure  quicker  than  the 
space  above  piston;  brake  pipe  pressure  will  then  raise 
piston  and  discharge  valve,  allowing  air  to  blow  out  of 
brake  pipe  exhaust  elbow  for  a  second  or  two.  There 
is  no  flash  of  air  from  the  type  H  brake  valve  when 
coupled  to  any  cars.  A  short  flash  of  air  comes  from  the 
H  type  when  additional  cars  are  cut  in,  if  the  H-5  valve 
is  on  lap,  the  H-6  on  running  position,  as  air  will  blow 
out  of  the  application  chamber  caused  by  the  brake  pipe 
reduction. 


BRAKE    PIPE    EXHAUST  71 

25.  Q.     Can   this   action   of  the   valve  be   of   advantage 
to  you? 

A.  Yes;  if  you  hear  this  escape  of  air  from  brake  pipe 
exhaust  when  releasing  brake  on  a  train,  it  is  a  sign  of  a 
short  brake  pipe;  and  is  a  notice  to  the  engineer  that  an 
angle  cock  at  the  head  end  of  train  is  closed,  or  something 
has  got  into  the  brake  pipe  and  stopped  it  up.  You  should 
see  at  once  if  an  angle  cock  is  not  shut  by  some  mistake 
or  malicious  intent.  Check  chains  swinging  against  the 
handle  will  close  it. 

26.  Q.     Does   the   amount   of   air   which   blows   out   of 
brake  pipe  exhaust  when  setting  the  brake  with  a  service 
application  give  you  any  idea  of  the  number   of  cars   in 
your  train  working  air? 

A.  Yes,  with  engine  and  tender  only,  the  brake  pipe 
exhaust  does  not  blow  much,  if  any,  longer  than  pre- 
liminary exhaust.  With  a  long  train  it  takes  some  seconds 
for  the  brake  pipe  pressure  to  be  reduced  and  equalize  its 
whole  length.  You  can,  after  some  practice,  tell  whether 
you  have  a  long  or  short  train  working  air  by  listening  to 
the  amount  of  air  escaping  from  barke  pipe  exhaust.  This 
test  shows  the  length  of  brake  pipe  cut  in  and  filled  with 
air,  not  the  number  of  brakes  that  set.  It  takes  consider- 
able practice  to  tell  how  many  cars  are  coupled  on.  By 
this  test  it  gives  the  number  of  car  lengths  of  brake  pipe 
in  use;  if  the  triple  is  cut  out  on  any  car  it  gives  you  no 
notice.  When  some  of  the  cars  are  cut  out  by  closing 
angle  cocks,  a  less  amount  of  air  will  come  out  than  with 
all  of  them.  It  is  important  to  know  this,  as  some  of  the 
angle  cocks  may  be  closed,  thus  cutting  off  all  the  cars 
behind  the  closed  one.  In  making  a  test  for  the  length  of 
brake  pipe  connected  to  the  brake  valve,  reduce  your  brake 
valve  pressure  exactly  five  pounds  by  the  gage  and  then 
note  the  amount  of  air  coming  out  of  the  brake  pipe  ex- 
haust. Always  use  the  same  amount  of  reduction  as  there 
is  no  sure  way  to  compare  the  length  of  brake  pipe  exhaust 
for  different  trains  unless  the  same  brake  valve  reduction 
is  used  as  a  measure  each  time.  A  partly  opened  angle 


72  DOUBLE    HEADING    COCK 

cock  can  be  detected  by  this  test,  for  the  air  will  flow  with 
a  strong,  steady  sound  from  the  brake  pipe  ahead  of  the 
partly  opened  cock,  while  the  air  from  the  pipe  behind  it 
will  string  out  longer  and  weaker  than  it  should.  Look 
out  for  this,  as  the  brakes  can  all  be  set,  but  as  the  air 
equalizes  very  slowly  into  the  rear  cars  some  of  the  triples 
in  rear  cars  are  liable  to  stick.  With  a  full  train  of  quick- 
service  triples  considerable  brake  pipe  air  goes  through 
these  triples  to  the  brake  cylinder;  so  a  less  amount  of  air 
will  come  out  of  the  brake  valve  from  the  brake  pipe  than 
with  the  older  form  of  triples. 

27.  Q.  What  is  the  stop  cock  under  brake  valve  for? 
Will  it  assist  you  in  locating  leaks?  How? 

A.  To  cut  out  the  brake  pipe  from  brake  valve  when 
double  heading,  so  only  one  engineer  can  control  all 
the  brakes.  For  this  purpose  it  is  absolutely  necesary. 
Yes,  it  will  assist  in  locating  leaks.  When  shut,  after 
charging  brake  pipe  and  auxiliaries,  if  there  is  a  leak  in 
brake  pipe,  brake  will  set  at  once ;  if  the  rotary  leaks  either 
into  or  our  of  the  brake  pipe,  it  will  show  it  very  soon,  as 
there  is  so  short  a  brake  pipe  to  leak  into  or  out  of.  A 
little  observation  will  teach  you  many  ways  of  using  this 
cut-out  cock  in  testing  for  leaks.  With  the  H-5  valve 
and  the  distributing  valve  this  stop  cock  controls  the  ex- 
haust from  the  distributing  valve. 

28.  Q.  If  you  had  an  1892  or  an  H-type  valve  and  the 
brake  would  not  go  on  in  service  application,  nor  the  black 
hand  fall,  nor  the  brake  pipe  exhaust  open,  while  air  came 
readily  from  preliminary  exhaust,  what  would  be  the 
matter  ? 

A.  I  would  look  for  a  leak  at  the  joint  on  lower  gasket 
where  a  leak  would  allow  air  to  get  from  main  reservoir 
direct  to  cavity  over  equalizing  piston  No.  47.  This  would 
give  main  reservoir  pressure  to  chamber  D  and  show  it  on 
the  black  hand.  A  brake  valve  with  this  leak  would  show 
very  little  or  no  excess  pressure.  No  air  could  come  out  of 
brake  pipe  exhaust,  as  the  pressure  could  not  be  reduced 
over  the  piston  so  valve  could  be  raised.  To  set  the  brake 


DISABLED   BRAKE   VALVE  73 

use  direct  application  port,  opening  and  closing  it  slowly. 

29.  Q.     If  you  had  a  continual  blow  at  the  brake  pipe 
exhaust  port  of  the  brake  pipe  valve  and  could  hold  no  air, 
where  would  the  difficulty  be  apt  to  be  found? 

A.  Stuck  or  leaky  equalizing  piston,  dirt  on  its  valve 
seat,  brake  valve  reservoir  bleed  cock  open,  or  bad  leak  in 
pipe  to  brake  valve  reservoir  or  gage.  Would  put  valve 
on  lap,  then  on  emergency  for  a  moment  and  see  if  that 
would  stop  it,  or  close  the  stop  cock  under  the  valve  and 
flash  the  valve  to  clean  off  the  seat.  • 

30.  Q.     How  should  the  brake  valve   handle  be  placed 
when    running    or    standing    with    brake    released,    unless 
auxiliaries  are  being  charged?     Why? 

A.  Always  in  running  position.  Because  this  is  the 
only  position  in  which  you  can  carry  excess  pressure, 
which  is  needed  to  release  brakes  promptly.  With  1892 
valve  on  full  release  the  brake  pipe  pressure  will  run  up  as 
high  as  pump  governor  will  allow ;  this  high  pressure  is 
apt  to  slide  the  wheels.  A  small  blow  hole  is  put  in  the 
rotary  valve  to  warn  engineer  that  valve  has  been  left 
in  full  release.  All  valves  should  have  this  warning  pott; 
if  it  gets  stopped  up,  it  is  a  sign  that  there  is  dirt  on 
top  of  rotary  valve,  which  should  be  taken  out  and  cleaned 
at  once.  When  on  running  position  the  opening  through 
brake  valve  from  main  reservoir  to  brake  pipe  is  a  smaller 
one  than  on  full  release.  If  the  train  breaks  in  two  or 
conductor's  valve  is  opened  to  stop  the  train  in  case  of 
accident,  the  brakes  will  operate  instantly  as  the  brake  pipe 
pressure  can  be  reduced  from  the  train  faster  than  the 
running  position  feed  port  can  supply  it.  If  the  valve  is 
on  full  release  the  brakes  will  not  set  tight  till  the  main 
reservoir  pressure  is  also  reduced.  If  necesary  to  hold 
engine  brakes  with  the  H-type  valve  after  a  release  of 
train  brakes,  use  holding  position. 

31.  Q.     What    are    the     essential    differences    between 
the  1892  model  and  the   1906  or  H-5  brake  valve? 

A.     The  H-5  brake  valve  has  all  the  pipe  connections 
made  at  the  bottom  section  or  pipe  bracket,  so  the  valve 


AUTOMATIC   BRAKE   VALVE 


H-5   BRAKE  VALVE  75 

can  be  removed  from  the  engine  without  disturbing  any 
pipe  joints.  The  feed  valve  is  located  on  a  pipe  between 
the  main  reservoir  and  brake  valve.  The  brake  valve 
receives  main  reservoir  air  direct  through  one  pipe.  .This 
air  comes  on  top  of  the  rotary.  Air  at  a  reduced  pressure 
comes  through  the  feed  valve  and  another  pipe;  coming 
under  the  rotary  at  port  d.  The  preliminary  e  and  emer- 
gency exhaust  x  is  through  the  center  of  the  rotary  o  into 
the  cavity  EX  in  section  3  of  the  valve  and  thence  to  the 
atmosphere.  The  brake  pipe  exhaust  is  at  the  bottom  and 
in  the  center  of  the  valve.  This  valve  is  intended  to  be 
used  in  connection  with  an  independent  brake  valve  and 
the  distributing  valve  for  the  locomotive  brake  and  has 
two  pipe  connections  for  this  purpose.  In  the  rotary  valve 
seat  there  is  a  port  /  that  connects  with  the  pipe  leading 
from  the  application  chamber  of  the  distributing  valve 
through  the  independent  brake  valve.  When  the  rotary 
is  in  running  position  port  h  in  the  rotary  registers  with  /, 
if  the  independent  valve  is  also  in  running  position,  the 
locomotive  brake  will  be  released. 

There  is  another  position  of  the  H-5  valve,  called  hold- 
ing position,  located  between 'running  and  lap,  in  which 
port  h  does  not  register  with  port  I,  but  air  corning  through 
the  feed  valve  can  pass  out  of  d  through  f  in  the  face  of 
the  rotary  into  b,  thence  through  a  cored  out  passage  to 
c  and  the  brake  pipe  leading  to  the  train.  With  the  H-5 
valve  in  holding  position  the  train  brake  will  be  re- 
leased and  the  locomotive  brake  held  set.  This  port  /  is 
also  lapped  in  full  release,  so  that  the  train  brake  can  be 
released  and  at  the  same  time  the  engine  brake  be  held 
set  if  required;  this  will  hold  the  slack  back  in  the  head 
end  of  the  train  and  make  it  safe  to  release  the  train  brake 
at  slow  speeds,  and  not  break  in  two.  Another  port  u  in 
the  rotary  seat  connects  with  the  double  heading  pipe,  port 
h  registers  with  u  in  lap  position.  This  pipe  leads  from 
the  exhaust  port  of  the  distributing  valve  and  is  only  used 
on  the  following  engine  of  a  double  header.  When  the 


76  H-5    BRAKE    VALVE 

double  header  cut  out  cock  under  the  brake  valve  is  closed 
this  pipe  connection  through  the  cock  is  open. 

In  the  emergency  position  of  the  rotary,  port  /  in  the 
seat  registers  v/ith  port  g  through  the  groove  n  in  the 
face  of  the  rotary  so  that  in  emergency  position  air  from 
the  brake  valve  reservoir  can  flow  into  application  chamber 
of  distributing  valve  and  apply  the  engine  brake  with 
greater  force.  Port  p  connects  with  the  excess  pressure 
head  of  the  pump  governor,  when  the  rotary  is  in  full  re- 
lease, running  or  holding  positions;  main  reservoir  air 
can  pass  through  port  ^  in  the  rotary  and  the  small  groove 
in  its  face  and  enter  port  p,  thus  controlling  the  excess 
presure  head  of  the  governor  in  these  positions.  In  full 
release  main  reservoir  air  from  port  ^  flows  through  the 
warning  port  r  into  EX  and  gives  the  warning  that  the 
valve  is  in  full  release  position.  In  service  position  port  h 
in  the  rotary  registers  with  e  in  the  seat,  air  from  cham- 
ber D  flows  into  o  and  EX,  all  other  ports  in  the  seat 
are  closed.  The  action  of  the  equalizing  piston  15  has 
already  been  described.  Cavity  k  in  the  face  of  the  rotary 
connects  ports  g  and  c  in  riming  and  holding  positions, 
so  that  brake  pipe  and  chamber  D  charge  up  alike  in  these 
positions  and  there  is  no  flash  of  air  from  the  brake  pipe 
exhaust  when  releasing  brakes  with  a  short  train. 

Plug  29  can  be  taken  out  and  some  good  oil  poured 
in  the  cavity  around  the  lower  edge  of  the  rotary  to  lubri- 
cate it.  Spring  30  holds  the  rotary  key  7  up  "against  gasket 
8  when  there  is  no  air  pressure  to  do  this.  In  full  release 
position  main  reservoir  air  passes  through  ports  a  in  the 
rotary  and  directly  into  port  b  and  the  brake  pipe,  and  port 
quickly.  In  running  and  holding  positions  cavity  /  in  the 
face  of  the  rotary  connects  ports  d  and  b  so  the  air  that 
has  been  reduced  in  pressure  at  the  feed  valve  can  flow 
into  the  brake  pipe  and  charge  it  -up  to  the  pressure  that 
the  feed  valve  closes  it,  and  no  higher.  To  take  the  H-5 
valve  off  its  pipe  bracket  take  out  the  through  bolts.  To 
take  the  valve  apart  take  out  the  tap  bolts  that  hold  the 
valve  sections  together. 


INDEPENDENT    BRAKE    VALVE  77 

32.  Q.     Describe    the    independent   brake    valve. 

A.  This  valve  is  used  in  connection  with  the  distribut- 
ing valve  and  allows  air  to  flow  into  or  out  of  the  applica- 
tion chamber,  and  thus  operate  the  supply  valve  piston, 
that  in  turn  operates  the  valves  which  admit  main  reser- 
voir air  to  the  brake  cylinder  to  set  the  engine  brake  or 
exhausts  the  cylinder  air  to  release  it.  It  does  not  admit 
main  reservoir  air  direct  to  the  brake  cylinder  as  the 
Straight  Air  brake  valve  does.  It  has  four  positions, 
release,  running,  lap  and  service,  that  come  the  same  as  on 
the  automatic  brake  valve.  A  stiff  spring  9,  in  the  top  of 
the  valve  body  3  returns  the  handle  from  release  to  run- 
ning position  as  soon  as  the  engineer  removes  his  hand. 

In  running  position  port  d  from  the  distributing  valve 
is  connected  through  port  f  in  the  rotary  5  with  port  c 
leading  to  the  automatic  valve,  so  that  air  can  flow  from 
the  application  chamber  through  the  independent  valve  to 
the  automatic  brake  valve,  and  this  valve  should  always 
be  in  running  position  when  the  automatic  valve  is  to 
operate  the  engine  brake.  In  release  position  cavity  g  in 
the  face  of  the  rotary  5  connects  port  d  with  the  exhaust 
port  h  in  the  center  of  the  seat,  so  that  the  application 
chamber  air  can  pass  to  the  atmosphere  without  regard  to 
the  position  of  the  automatic  brake  valve  and  release  the 
engine  brake  independently  of  the  train  brake.  In  service 
position  cavity  e  in  the  rotary  connects  the  supply  port  b 
with  d  so  that  main  reservoir  air  reduced  to  45  pounds  can 
flow  direct  to  the  application  chamber  and  operate  the  dis- 
tributing valve  supply  piston;  this  position  applies  the 
engine  brake  independently.  Lap  position  blanks  all  ports 
and  is  to  be  used  only  when  making  a  graduated  applica- 
tion or  release  of  the  engine  brake  or  when  trying  to 
prevent  the  release  of  the  engine  brake  by  the  automatic 
valve,  or  the  passage  of  air  from  the  brake  valve  reser- 
voir through  the  automatic  valve  in  the  emergency  posi- 
tion to  the  application  chamber.  Leaving  the  independent 
valve  in  lap  position  when  operating  the  automatic  valve 


78 


INDEPENDENT   BRAKE   VALVE 


is  liable  to  cause  trouble.     This  valve  does  not  affect  the 
operation  of  the  train  brake  in  any  way  and  is  to  be  used 


INTERIOR  VIEWS  OF  THE  INDEPEND 
-ENT  BRAKE  VALVE 

when  "Operating  the  engine  brake  while  switching  cars, 
or  independently  at  any  time.  Its  supply  of  air  comes 
from  the  main  reservoir  through  a  reducing  valve  set  at 
45  pounds.  The  arrangement  of  these  valves  is  shown  in 
the  page  illustration  and  they  are  part  of  the  ET  locomo- 
tive brake  equipment.  The  location  of  each  valve  in  this 
type  of  brake  is  plainly  shown,  so  no  description  is  given. 

33.  Q.  Describe  the  distributing  valve  in  its  construc- 
tion and  operation. 

A.  The  distributing  valve  is  shown  separately  and 
attached  to  its  double-chambered  reservoir.  The  pressure 


80 


THE    DISTRIBUTING    VALVE 


chamber  represents  an  auxiliary  reservoir  and  the  applica- 
tion chamber  the  brake  cylinder  as  regards  the  equaliza- 
tion when  the  air  passes  to  the  application  chamber;  this 
comparison  is  for  explanatory  purposes  only.  There  are 
five  pipe  connections,  only  two  of  which  show  on  the  ex- 


posed  side  of  the  reservoir.  On  the  next  page  is  shown  a 
diagrammatic  view  of  the  valve  and  reservoir,  in  which 
the  valve  is  shown  much  larger  in  proportion  to  the  size 


5  2 

2  I* 

z  o 


CO 

m 
2 
m 


APPLI- 

;•: 

y 
/ 

- 

y 
y 

CATION 

;/; 

PRESSURE           VL 

CHAMBER. 

f// 

CHAMBER 

X 

X 

/ 
/ 

y 

/ 

^ 

>»»»»»,»»»»»^ 

RELEASE,  AUTOMATIC  OR 
INDEPENDENT 


82  THE    DISTRIBUTING    VALVE 

of  the  reservoir  than  it  really  is.  We  will  use  capital  let- 
ters as  abbreviations  for  the  names  of  the  five  pipe  connec- 
tions made  to  the  reservoir  and  from  there  to  the  various 
parts  of  the  valve.  In  the  diagrammatic  view  slide  valve 
31  and  graduating  valve  28  are  shown  both  above  and 
below  the  piston  stem  26,  so  the  ports  that  are  beside  each 
other  can  be  seen.  Air  from  main  reservoir  enters  at  sup- 
ply, passes  through  port  a  up  and  around  application  valve 
5 ;  also  down  to  seat  of  slide  valve  31  and  through 
port  n  to  the  pressure  chamber  when  valve  31  is  in 
emergency  position.  Air  from  the  brake  pipe  enters  at 
BP  and  is  on  the  outside  of  equalizing  piston  26.  When 
this  piston  is  in  release,  as  shown,  brake  pipe  air  can  pass 
around  the  piston  through  the  feed  port  into  the  pressure 
chamber.  When  thte  brake  pipe  pressure  is  reduced  piston 
26  moves  back  towards  the  reducing  train  pipe  pressure, 
bringing  first  graduating  valve  28  and  then  moving  slide 
valve  31  as  soon  as  the  lost  motion  between  the  shoulders 
on  piston  stem  and  valve  31  is  taken  up.  This  admits 
air  from  the  pressure  chamber  to  the  application 
chamber  through  ports  o  and  h,  and  in  this  respect  is 
exactly  like  a  triple  valve  when  feeding  air  from  the 
auxiliary  to  the  brake  cylinder.  With  a  partial  application 
of  the  automatic  brake  equalizing  piston  26  and  its 
valves  reduces  the  pressure  in  the  pressure  chamber  by 
allowing  air  to  pass  into  the  application  chamber  till  the 
pressure  chamber  is  a  trifle  lower  than  the  brake  pipe 
when  piston  26  moves  back  and  laps  graduating  valve  28. 
This  movement  has  been  fully  explained  in  connection 
with  the  triple  valve. 

At  the  same  time  that  air  flows  into  the  application 
chamber,  it  also  flows  up  through  port  h  into  the  space  g 
behind  the  application  piston  10.  This  moves  application 
valve  5  and  as  soon  as  the  lost  motion  is  taken  up, 
exhaust  valve  16  covers  the  exhaust  ports  e  and  d. 
Valve  5  next  opens  the  supply  port  from  a  into  b  and  c, 
so  main  reservoir  air  can  flow  to  the  brake  cylinder  at  BC 
and  apply  brake.  We  will  suppose  a  7-pound  reduction 


OPERATION     OF     DISTRIBUTING     VALVE  83 

is  made  in  the  brake  pipe.  As  soon  as  it  is  felt  on  the 
piston  26  at  p  it  will  move  towards  BP,  open  valves  28 
and  31  closing  exhaust  port  k  Air  will  flow  into  the 
application  chamber  and  cavity  g  till  the  pressure  cham- 
ber is  also  reduced  7  pounds,  when  piston  26  will  move 
back  and  lap  valve  28  over  the  port  in  valve  31.  Air 
pressure  in  g  will  then  move  piston  10  and  its  valves 
3  and  16,  closing  the  exhaust  ports  c  and  d  and  opening 
supply  port  from  a  to  c.  To  open  port  from  a  the  gradu- 
ating stem  19  must  be  moved  back  against  the  tension  of 
its  spring  20,  when  the  stem  19  meets  cap  nut  22.  As 
soon  as  the  presure  in  b  and  the  engine  brake  cylinders 
is  equal  to  that  in  that  in  g  on  the  other  side  of  piston  10, 
spring  20  and  the  stem  19  will  move  piston  10  and  valve  5 
back  to  lap,  but  does  not  move  valve  16  to  open  the  ex- 
haust. This  applies  the  brake  and  holds  it  applied  as  long 
pressure  remains  in  g  and  h.  If  leaks  in  the  brake  cylin- 
der packing  or  piping  reduce  the  pressure  in  bf  piston  10 
will  move  towards  this  lecreasing  pressure  and  open  the 
supply  port  till  the  pressure  in  the  cylinder  again  equals 
that  in  g,  when  piston  10  will  lap  valve  5.  When  the  air  in 
the  application  chamber  is  either  wholly  or  partly  ex- 
hausted to  the  atmosphere,  piston  10  will  be  moved  back 
towards  g  by  the  brake  cylinder  pressure  and  either  wholly 
or  partly  exhaust  the  air  from  the  cylinder. 

In  the  independent  application  and  release  of  the 
brake  through  the  distributing  valve  the  lower  or  equal- 
izing piston  26  and  its  valves  do  not  move.  The  air  is  fed 
into  and  out  of  the  application  chamber  and  chamber  g 
by  the  independent  brake  valve  at  the  pipe  connection  AC. 
This  air  comes  from  the  main  reservoir  and  is  reduced  to 
45  pounds  presure  befoure  passing  through  the  independent 
brake  valve.  When  the  independent  valve  is  in  service 
position  air  flows  in  at  AC  till  the  pressure  in  the  appli- 
cation chamber  and  g  is  enough  to  apply  the  brake  the 
desired  amount.  A  partial  or  full  application  can  be  made 
depending  on  how  much  air  is  admitted  through  the  brake 
valve,  and  a  partial  or  full  release  by  lapping  the  brake 


84  OPERATION    OF    DISTRIBUTING    VALVE 

valve  before  all  the  air  has  escaped.  To  prevent  the  air 
passing  out  the  exhaust  port  k  of  valve  31  when  in  re- 
lease position  port  i  is  piped  at  DH  to  the  double  heading 
cock  in  the  brake  pipe  under  the  automatic  brake  valve. 
When  this  cock  is  open  for  the  brake  pipe,  as  it  should  be 
when  the  automatic  brake  is  being  operated  from  that 
engine,  the  pipe  leading  from  the  exhaust  port  k  is  closed 
so  no  air  can  escape  through  valve  31  when  in  release 
position.  But  if  this  engine  is  not  operating  the  train 
brake  in  a  double  header  the  exhaust  port  k  is  open 
through  a  pipe  from  DH  through -the  cut-out  cock  and  a 
port  in  the  H-5  automatic  brake  valve  when  the  rotary 
is  in  lap  position. 

There  is  a  cut-out  cock  in  the  brake  pipe  connection 
before  reaching  BP  to  cut  out  the  distributing  valve  from 
operating  automatically  when  necessary.  Closing  this  cut- 
out cock  does  not  prevent  the  brake  being  operated  by 
the  independent  brake  valve. 

When  the  automatic  brake  valve  is  in  the  emergency 
position  air  from  the  brake  valve  reservoir  can  flow 
through  a  port  in  the  H-5  valve,  then  through  the  inde- 
pendent valve — if  it  is  in  running  position — into  the 
application  chamber  and  gf  so  that  the  engine  brake  can 
be  applied  in  that  position  of  the  automatic  valve,  even 
if  cut  out  from  the  brake  pipe.  This  is  a  feature  of  the 
H-5  only. 

When  piston  26  is  moved  its  full  travel  to  the  emer- 
gency application  position  so  it  rests  against  gasket  25  in 
cap  23,  ports  n  in  the  bushing  and  m  in  valve  31  will  be 
open  to  each  other  so  main  reservoir  air  can  flow  slowly 
through  the  small  port  n  into  the  pressure  chamber  and 
increase  the  pressure  there.  At  the  same  time  port  /  is 
open  to  the  safety  valve  34  and  it  will  reduce  the  pressure 
there  to  about  60  pounds.  This  feature  is  intended  to 
operate  the  brake  the  same  as  the  high  speed  reducing 
valve.  In  the  No..  5  distributing  valve  (the  one  here 
described),  port  /  is  only  open  to  the  pressure  chamber 


NO.     6    E.    T.    EQUIPMENT 


85 


and  port  h  in  application  position;  being 
closed  in  release  and  lap  positions  of  valve 
28  and  31.  For  this  reason,  when  using  the 
independent  brake  valve  only  with  the  equal- 
izing piston  26  in  release  or  lap  the  safety 
valve  34  will  not  reduce  the  pressure  in  the 
application  chamber  should  the  reducing  valve 
for  the  independant  valve  be  out  of  order  and 
allowing  too  high  a  pressure.  This  safety 
valve  is  set  at  53  pounds,  and  will  blow  down 
Lto  that  with  an  automatic  service  application. 
34.  Q.  Are  there  any  differences  between  the  No. 

5  ET  equipment  and  the  later  design,   No.   6?     Describe 
them. 

A.  The  No.  6  ET  equipment  was  designed  later 
than  the  No.  5  just  described,  there  are  several  differences 
between  the  No.  6  and  any  previous  type  that  enable  No. 

6  to   get  the   same   results    easier    and   have   many   added 
advantages. 

The  release  pipe  between  the  automatic  brake  valve 
and  the  independent  valve  goes  direct  and  not  through 
the  double  heading  cock,  the  double  heading  cock  of  the 
H-6  is  an  ordinary  stock-cock  the  same  as  used  with  the 
F-6  valve.  In  double-heading  the  normal  position  of  the 
H-6  valve  is  running  instead  of  lap  as  with  the  H-5.  The 
release  pipe  from  the  distributing  valve  comes  from  the 
application  cylinder  with  No.  5  and  from  the  exhaust  of 
equalizing  slide  valve  31  with  No.  6,  so  that  valve  31 
must  be  in  release  position  to  release  the  distributing 
valve  through  the  H-6  valve.  With  No.  5,  air  could 
come  out  of  the  application  cylinder  and  chamber  through 
the  two  brake  valves  in  running  position  regardless  of  the 
position  of  slide  valve  31.  The  application  cylinder  pipe 
of  No.  6  goes  direct  to  the  independent  valve  as  before, 
a  Tee  connection  is  put  in  leading  to  the  H-6  maintaining 
port.  In  No.  5  this  port  was  in  the  distributing  valve. 

In  an  emergency  application  with  the  No.  6  slide  valve 
31  moves  quickly  and  laps  the  port  into  the  application 


No.     6     DISTRIBUTING     VALVE  87 

chamber  so  the  pressure  chamber  equalizes  with  the 
application  cylinder  only,  at  very  nearly  the  amount  of 
pressure  in  the  chamber  at  first,  about  65  out  of  70 
pounds.  In  a  service  application  the  port  to  the  applica- 
tion chamber  is  held  open  so  the  pressure  chamber  equal- 
izes with  the  combined  volume  of  the  application  chamber 
and  cylinder  at  50  out  of  70  pounds. 

The  positions  of  the  two  smaller  pipes  at  the  bottom 
of  the  distributing  valve  are  reversed  in  No.  6  from  that 
in  No.  5.  The  application  cylinder  pipe  is  the  lower  one 
in  No.  5  it  is  the  upper  one  in  No.  6 ;  the  lower  one  in 
No.  6  connects  with  the  exhaust  of  valve  31.  In  No.  5 
the  double  heading  pipe  that  did  this  work  was  the  upper 
one. 

There  is  a  special  cap  for  the  cylinder  of  piston  26, 
containing  a  quick-action  valve  to  vent  brake  pipe  air 
to  the  brake  cylinders  and  a  rubber  seated  check  to  hold 
it  there,  this  will  hurry  up  the  quick-action  on  the  train 
as  a  quick-action  triple  on  a  tender  will  do. 

There  is  only  one  position  of  slide  valve  31  of  the  No. 
6  in  which  safety  valve  43  is  not  connected  to  the  applica- 
tion cylinder,  automatic  lap,  in  all  other  positions  the 
safety  valve  will  take  care  of  the  over  pressure. 

A  careful  study  of  the  explanation  of  the  No.  5  will 
assist  in  understanding  the  No.  6,  the  points  that  are 
common  to  both  valves  need  not  be  explained  again. 

35.  Q.     Describe  the  H-6  brake  valve  and  its  operation. 

A.  The  H-6  valve  is  similar  in  outside  shape  to  the 
H-5;  there  are  differences  in  the  air  ports  and  cavities; 
using  the  cut  of  the  rotary  and  its  seat  to  trace  the  course 
of  the  air  in  different  positions  will  give  a  good  idea  of 
the  work  of  the  valve.  It  has  six  positions;  full  release, 
running,  holding,  lap,  service  application  and  emergency. 
Main  reservoir  air  comes  in  over  the  rotary  valve  at 
MR;  feed  valve  air  at  FV  under  the  rotary  at  port  d; 
b  is  the  supply  port  through  the  seat  for  the  brake  pipe 
and  c  the  emergency  exhaust  from  the  brake  pipe,  o  is 


88  NO.    6    DISTRIBUTING   VALVE 

the  exhaust  opening  and  x  the  emergency  exhaust  passage 
in  the  rotary;  f  connects  d  and  b  in  running  position. 

In  full  release,  port  a  through  the  rotary  registers 
with  port  b,  the  brake  pipe;  so  main  reservoir  air  at  full 
pressure  goes  directly  to  the  brake  pipe  in  this  position ; 
j  in  the  rotary  registers  with  g  in  the  seat,  so  chamber 
D  charges  with  main  reservoir  air  direct  in  this  position; 
Cavity  /  in  the  face  of  the  rotary  connects  port  d  with 
warning  port  r  in  the  seat  and  allows  a  small  amount  of 
feed  valve  air  to  escape  to  the  atmosphere,  serving  two 
purposes  warning  the  engineer  to  move  the  valve  from 
full  release  and  giving  an  idea  of  how  sensitive  the  feed 
valve  is.  Port  ^  through  the  rotary  has  a  small  groove 
at  the  face,  this  connects  with  port  p  in  the  seat  allowing 
main  reservoir  air  to  flow  to  the  lower  connection  of  the 
excess  head  of  the  pump  governor  in  full  release,  running 
and  holding  positions. 

In  running  position  port  a  through  the  rotary  is  closed 
at  its  lower  end  so  no  main  reservoir  air  can  go  directly 
to  tne  brake  pipe,  cavity  f  connects  d  and  b  so  air  from 
the  feed  valve  can  flow  to  the  brake  pipe;  cavity  k  con- 
nects ports  c  and  g,  the  brake  pipe  and  chamber  D  can 
now  equalize.  Port  s  still  registers  with  por£  p  leading  to 
the  governor,  h  in  the  rotary  registers  with  /  in  the  seat 
that  connects  with  the  release  pipe  and  allows  air  ex- 
hausted through  valve  31  from  the  application  cylinder 
and  chamber  to  escape  and  release  the  locomotive  brake. 

When  an  empty  train  is  being  charged,  as  long  as  the 
brake  valve  is  in  full  release  the  pump  will  run  at  speed, 
but  when  the  valve  is  moved  to  running  position  the 
action  of  the  S-F  pump  governor  is  sometimes  puzzling. 
As  one  side  of  this  governor  is  operated  by  the  excess 
pressure  if  the  feed  valve  cannot  pass  the  air  to  the 
brake  pipe  as  fast  as  the  pump  supplies  it,  the  excess 
will  build  up  enough  between  the  main  reservoir  and 
brake  pipe  pressures  to  have  the  governor  stop  the  pump. 
In  such  a  case  move  brake  valve  to  full  release  and  leave 


—THE  H-6  AUTOMATIC  BRAKE  VALVE 

it    there    till    the    brake    pipe    pressure    is    close    to    the 
standard. 

Holding  position  leaves   all  the  ports   that  were   open 


90  H-6  BRAKE  VALVE  POSITION 

in  running  position  still  open,  except  I,  that  is  now  lapped 
instead  of  being  open  to  h,  the  distributing  valve  cannot 
release  through  that  port.  This  position  will  release  and 
charge  up  all  the  automatic  parts  of  the  brake  on  train 
and  engine,  but  hold  the  engine  brake  set. 

On  lap  position  all  ports  in  the  rotary  and  its  seat 
are  lapped;  there  is  no  passage  for  air  in  any  direction 
through  the  ports. 

On  service  position  all  ports  are  lapped,  except  the 
preliminary  exhaust  port  e,  this  registers  with  h  in  the 
rotary,  the  air  in  chamber  D  will  now  pass  out  slowly, 
brake  pipe  air  will  raise  equalizing  piston  15  and  its 
valve  and  discharge  brake  pipe  air  to  the  atmosphere. 

When  the  H-6  is  placed  in  emergency  position,  port 
x  in  the  rotary  registers  with  c  in  the  seat,  making  a 
large  opening  from  brake  pipe  to  atmosphere  through  o 
in  the  rotary  and  EX  in  the  seat.  The  sudden  reduction 
in  brake  pipe  pressure  starts  the  quick-action  in  the  train 
brakes  and  applies  all  of  them  in  the  shortest  space  of 
time.  Main  reservoir  air  is  now  passing  through  port  / 
in  the  rotary,  thence  through  a  small  port  into  cavity  k 
and  small  port  n  into  port  u  in  the  seat,  and  thence 
through  the  Tee  connection  into  the  application  cylinder; 
this  maintains  the  pressure  in  this  cylinder  up  to  when 
the  safety  valve  controls  it.  Port  t  in  the  rotary  registers 
with  equalizing  port  g,  air  in  chamber  D  will  pass  out  to 
the  atmosphere  instead  of  going  to  the  application  chamber 
as  it  does  with  H-5. 

36.  Q.     Describe    the     S-6     independent     brake     valve. 

A.  The  independent  brake  valve  S-6  has  five  posi- 
tions :  Release,  Running,  Lap,  Slow  Application  and  Quick 
Application.  A  return  spring  6,  coiled  inside  the  top  of 
the  valve  will  return  the  handle  15  from  release  to  run- 
ning, and  from  quick  application  to  slow  application;  the 
engineer  will  feel  the  resistance  of  this  spring  when  mov- 
ing the  rotary  to  its  full  travel,  either  way.  The  warning 
port  /  is  provided  to  warn  the  engineer  in  case  this  spring 
is  broken.  Air  from  the  reducing  valve  at  45  pounds 


S-6     INDEPENDENT    VALVE 


91 


THE  S=6  INDEPENDENT  BRAKE  VALVE 

pressure  comes  in  at  port  b  and  on  top  of  rotary  through 
port  e.  Port  a  leads  air  through  the  release  pipe  IV  from 
the  distributing  valve  exhaust  of  slide  valve  31;  port  c 
connects  with  the  release  pipe  to  H-6  at  port  e]  ports 
a  and  c  are  connected  by  groove  /  in  the  rotary  9  when 
in  running  position;  with  both  valves  in  running  position, 
air  exhausted  by  slide  valve  31  can  pass  through  the 
S-6  and  escape  at  the  H-6  valve.  Port  d  leads  to  the 
application  cylinder  pipe  II,  in  independent  application 
air  passes  in  through  this  port  and  pipe  to  application 
cylinder;  in  independent  release  air  passes  out  this  way. 
A  Tee  in  this  pipe  leads  to  the  maintaining  port  u  in  the 


92  NO.    6    DISTRIBUTING    VALVE 

H-6  rotary,  h  is  the  exhaust  port,  exhaust  cavity  g  in 
rotary  9. always  registers  with  it.  k  is  the  warning  port,  » 
is  the  warning  port  in  the  rotary,  open  in  release.  A 
small  port  m  connects  with  groove  e  and  registers  with  d 
in  slow  application,  passing  air  slowly;  in  quick  applica- 
tion position  the  larger  groove  e  registers  with  d  and 
passes  a  large  amount  of  air  to  the  application  cylinder, 
setting  the  brake  quickly.  The  latter  part  of  answer  to 
Q.  32  gives  directions  for  operating  this  valve. 

37.  Q.  Explain  the  operation  of  the  No.  6  Distribut- 
ing Valve. 

A.  The  diagrammatic  view  of  the  No.  6  distributing 
valve  gives  a  good  idea  of  the  application  portion  at  the 
top  of  the  cut;  the  equalizing  portion  is  in  the  middle; 
the  double  chambered  reservoir  is  at  the  bottom;  for 
the  reference  letters  and  .numbers,  look  at  the  next 
diagrammatic  cut.  Main  reservoir  air  comes  into  the 
application  portion  only,  a  pipe  leads  to  the  brake  cylin- 
ders. The  movement  of  the  application  piston  and  its 
two  valves  admits  main  reservoir  air  to  the  brake  cylin- 
ders or  exhausts  cylinder  air  to  the  atmosphere.  Admit- 
ting air  at  a  pressure  into  the  application  cylinder  will 
move  piston  10  and  its  valves  to  the  right,  first  closing 
exhaust  ports  under  valve  16,  next  opening  air  port  under 
valve  5,  so  main  reservoir  air  can  flow  to  the  cylinders. 
If  we  have  put  10  pounds  pressure  against  piston  10  and 
opened  the  air  port,  air  will  flow  in  till  the  brake  cylinder 
pressure  builds  up  to  10  pounds;  piston  10  will  then  be 
balanced  between  the  two  pressures;  a  graduating  stem 
19,  and  its  spring  20,  in  the  end  of  the  piston  stem  will 
move  the  piston  and  valve  5  back  to  lap.  Increase  the 
pressure  in  application  cylinder,  piston  10  and  valve  f> 
will  move  to  admit  more  air,  when  pressures  are  balanced; 
valve  5  will  close,  thus  the  pressure  can  be  built  up  in  the 
brake  cylinder  by  admitting  air  to  the  application  cylinder. 
To  release  the  brake,  allow  part  or  all  of  the  application 
cylinder  air  to  escape;  piston  10  will  be  moved  to  the 
left  by  brake  cylinder  pressure,  opening  the  ports  under 


DIAGRAMMATIC   DISTRIBUTING  VALVE  93 

valve  16  the  brake  will  then  be  all  or  partly  released,  de- 
pending on  the  pressure  left  in  the  application  cylinder. 
It  leaks  in  the  brake  cylinder  reduce  pressure  there,  piston 


I     TO  MAW  fl 


TO  INDEPENDENT  BRAKE  VALVE. 


DIAGRAMMATIC  VIEW  OP  THE  ESSENTIAL 
PARTS  OF  THE  DISTRIBUTING  VALVE,  AND 
DOUBLE-CHAMBER  RESERVOIR. 


94  OPERATION    OF    DISTRIBUTING    VALVE 

10  will  move  to  the  right,  open  supply  valve  5  and  build 
the  brake  pressure  up  to  equal  that  in  the  application 
cylinder;  leaks  out  of  the  application  cylinder  or  its 
piping  will  tend  to  release  the  brake.  There  are  two 
ways  of  letting  pressure  into  and  out  of  the  application 
cylinder;  one  by  way  of  the  independent  valve  and  H-6 
valve,  the  other  is  by  the  operation  of  the  equalizing 
portion  of  the  distributing;  this  is  shown  clearly  in  the 
diagrammatic  view  of  automatic  service.  The  brake  pipe 


MR 


AUTOMATIC  SERVICE 


OPERATION     OF     THE     DISTRIBUTING     VALVE  95 

connection  supplies  brake  pipe  air  to  this  portion  the  same 
as  to  a  triple;  air  feeds  around  piston  26,  through  feed 
port  r  charging  up  the  space  around  valve  31 ;  passes 
through  port  o  into  the  pressure  chamber  till  the  pressure 
there  equalizes  with  the  brake  pipe.  To  make  an  auto- 
matic service  application  of  the  distributing  valve,  the 
brake  pipe  pressure  is  reduced,  piston  26  at  once  moves 
to  the  right,  a  part  of  its  full  travel  to  the  position  shown 
in  the  view;  first  moving  graduating  valve  28  to  open 
port  2  and  closing  feed  port  v.  Slide  valve  31  is  next 
moved  to  register  ports  z  and  h,  air  from  the  pressure 
chamber  flows  through  z,  h,  and  w  into  both  application 
chamber  and  application  cylinder  g,  building  up  a  press- 
ure against  piston  10.  Safety  valve  /  is  now  connected 
through  ports  r  and  s  with  h;  this  allows  application 
cylinder  air  access  to  the  safety  valve.  Suppose  we  make 
a  7-pound  reduction  in  brake  pipe  and  move  piston  26  and  its 
valves,  as  soon  as  the  air  in  the  pressure  chamber  and  on  that 
side  of  piston  26  is  reduced,  a  little  more  than  7  pounds  by 
going  into  the  pressure  chamber  and  g;  piston  26  will 
move  towards  this,  decreasing  pressure,  covering  port  z 
with  valve  28;  no  more  air  will  pass  out  of  the  pressure 
into  the  application  chamber  and  g ;  the  action  in  this 
respect  is  like  a  triple  valve  feeding  air  from  an  auxiliary 
to  a  brake  cylinder,  described  on  page  8. 

Another  brake  pipe  reduction  will  send  more  air  from 
the  pressure  to  the  application  chamber  and  g,  till  the 
pressures  in  these  two  chambers  are  equalized,  after  that 
the  pressure  in  g  cannot  rise  any  higher  with  ah  auto- 
matic application.  A  pressure  built  up  in  g  will  operate 
piston  10  and  its  valves  to  send  main  reservoir  air  to  the 
brake  cylinders ;  exhausting  air  from  g  will  release  the 
brake.  To  release  the  engine  brake  automatically,  re- 
charge the  brake  pipe  till  its  pressure  will  move  piston 
26  and  valve  31 ;  to  release  position  air  from  g  and  the 
application  chamber  will  then  pass  out  under  valve  31 
through  pipe  IV  to  the  brake  valves,  with  both  of  them 
in  running  position  this  air  can  get  to  the  atmosphere, 


96 


OPERATION    OF    THE    DISTRIBUTING    VALVE 


piston    10    will    then    open    exhaust    valve    16    and    release 
the  brake. 

In  the  independent  application  and  release  of  the  brake 
through  the  distributing  valve,  lower  piston  26  and  its 
valves  do  not  move,-  but  remain  in  the  position  they  have 
been  placed  in  by  the  automatic  brake  valve,  changes  in 
brake  pipe  and  pressure  chamber  pressures  move  this 
piston. 


32 


EMERGENCY  POSITION  OF  No.  6  DISTRIB- 
UTING VALVE  WITH  QUICK-ACTION  CAP. 


QUICK-ACTION    DISTRIBUTING    VALVE  97 

The  No.  6  valve  is  provided  with  a  quick-action  cap 
47,  that  can  be  used  in  place  of  the  plain  cylinder  cap 
23  on  large  passenger  engines  or  those  used  in  double- 
heading  regularly.  This  cap  47  contains  an  emergency 
valve  48  attached  to  the  graduating  stem  50,  so  they  move 
together  and  a  rubber  seated  check  53,  and  its  spring  54, 
that  opens  to  admit  brake  pipe  air  to  passage  m,  leading 
to  the  brake  cylinder  pipe  at  c.  An  over-reduction  of 
brake  pipe  air  in  service  application  will  move  stem  50 
and  valve  48  to  open  port  /,  but  in  this  application  brake 
cylinder  has  equalized  with  brake  pipe  and  no  air  will 
pass  the  check-valve  53.  When  a  sudden  and  heavy 
reduction  in  brake  pipe  pressure  is  made  as  the  first 
reduction,  piston  26  moves  its  full  travel,  at  once  push- 
ing stem  50  over  against  the  resistance  of  spring  55, 
moving  valve  48  to  uncover  port  /;  this  makes  a  sudden 
reduction  of  brake  pipe  air  that  will  insure  the  quick- 
action  of  triples  on  the  train  in  the  same  way  a  quick- 
action  triple  on  the  tender  will.  When  the  brake  pipe 
air  equalizes  with  the  brake  cylinder,  check-valve  53 
closes  so  air  can  not  pass  back  from  the  cylinders.  Air 
from  the  pressure  chamber  flashes  into  the  application 
cylinder  and  operates  piston  10  to  set  the  brake  when 
this  sudden  reduction  operates  piston  26.  Valve  31  passes 
over  port  w  so  quickly  that  very  little  air  gets  into  applica- 
tion chamber,  pressure  chamber  air  equalizes  with  applica- 
tion cylinder  g  only  at  very  near  its  original  pressure, 
about  65  out  of  70  pounds  and  sets  the  brake  at  that 
pressure. 

If  the  H-6  valve  is  left  in  emergency  position  its 
maintaining  port  u  will  pass  main  reservoir  air  through 
pipe  II  and  build  up  the  pressure  in  g  till  the  safety  valve 
set  at  68  pounds  can  control  it. 

In  High  Speed  Brake  service  with  the  feed  valve 
carrying  110  pounds  instead  of  70,  the  main  reservoir 
pressure  is  usually  130  to  140  pounds;  this  pressure  at  the 
H-6  valve  will  force  more  air  through  port  w  and  raise 
the  pressure  in  g  to  about  93  pounds.  The  small  opening 


98  DOUBLE     HEADING 

between  q  and  r  in  slide  valve  31  is  just  enough  larger 
than  port  w  so  the  air  can  be  reduced  to  75  pounds  by 
^the  safety  valve;  this  higher  pressure  gives  a  quicker 
stop  in  High  Speed  service.  When  the  H-6  brake  valve 
is  put  in  release  position,  after  an  emergency  stop,  and 
the  brake  pipe  pressure  is  built  up  enough  to  move  piston 
26  to  release,  the  air  in  the  application  cylinder  can  then 
equalize  into  the  application  chamber  at  about  15  pounds ; 
this  will  hold  the  locomotive  brake  set  at  that  pressure 
till  the  H-6  is  moved  to  running  position,  it  will  then 
fully  release. 

In  double  heading  the  cock  under  the  H-6  brake  valve 
must  be  closed  on  the  following  engines  to  give  the  lead- 
ing engineer  control  of  the  brakes  and  the  H-6  and  S-6 
valves  carried  in  running  position;  this  will  leave  the 
exhaust  port  of  valve  31  open  to  the  atmosphere  so  the 
leading  engineer  can  use  the  distributing  valves  on  the 
following  engines,  the  same  as  triple  valves  on  the  train. 
If  necessary  to  release  the  engine  brake  on  the  following 
engines,  it  should  be  done  with  the  independent  brake 
valve  without  moving  the  H-6  from  running  position. 
When  backing  up  a  train  that  is  to  be  controlled  with  a 
tail  hose,  the  H-6  should  be  carried  in  running  position, 
unless  the  rules  of  the  Company  require  another  position. 


COMBINED  AIR  STRAINER  AND  CHECK 
VALVE 

There  is  a  connection  from  the  brake  pipe  to  the  main 
reservoir  pipe  with  a  stop-cock  to  keep  it  cut  out  when 
not  needed,  and  a  strainer  check  valve  to  prevent  air 
from  coming  back  from  the  reservoir;  this  for  use  on 


DEAD    ENGINE    CONNECTION  .  99 

a  dead  engine  when  drawn  in  a  train.  This  connection 
will  furnish  a  supply  of  air  to  operate  the  E.  T.  brake ; 
the  check  valve  is  held  down  by  a  20  pound  spring,  with 
70  pounds  in  the  brake  pipe  there  will  me  50  in  the  main 
reservoir.  A  choke  in  the  check  case  prevents  air  flowing 
out  of  the  brake  pipe  fast  enough  to  affect  the  brakes. 
The  same  type  of  strainer  check  without  a  spring  is  used 
between  the  45-pound  reducing  valve  and  the  signal 
system.  The  piping  diagram  shows  the  location  of  these 
strainer  checks. 

When  making  a  ''two-application"  stop  with  a 
passenger  train  and  ready  to  make  the  first  release ;  go 
to  release  position  just  long  enough  to  move  all  the 
triples,  then  to  running  for  an  instant  to  allow  the  engine 
brake  to  release;  the  engineer's  judgment  must  decide 
how  long;  you  can  then  come  to  lap  or  service  to  make 
the  second  application;  unless  you  stop  an  instant  on  run- 
ning the  engine  brake  will  remain  full  set. 

When  operating  the  locomotive  brake  separately  from 
the  cars,  use  the  independent  valve,  leaving  the  H-6  in 
running  position.  A  partial  or  full  application  can  be 
made  by  admitting  a  little  or  much  air,  and  a  partial  re- 
lease by  lapping  the  independent  valve  before  all  the 
air  has  escaped  from  the  distributing  valve.  This  valve 
can  be  used  to  bunch  or  hold  the  slack  as  well  as  to 
hold  the  engine  brake  set  when  standing  at  a  water  plug 
or  on  a  grade. 

To  cut  out  the  brake  pipe  from  the  distributing  valve 
there  is  a  stop-cock  in  the  branch  pipe,  and  to  cut  out  the 
driver  or  tender  brake  cylinders  when  disabled,  there  are 
cocks  in  the  proper  pipes.  A  choke  fitting  near  the  hose 
connection  to  the  tender  brake  will  hold  the  driver  brakes 
set  if  the  hose  bursts  or  is  uncoupled,  as  the  distributing 
valve  can  feed  air  in  faster  than  it  can  get  through  the 
choke.  The  choke  is  large  enough  to  allow  the  tender 
brake  to  set  and  release  without  delay. 

The  E.  T.  equipment  must  be  kept  clean  and  all  the 
pipe  joints  and  gaskets  air  tight  if  it  is  to  operate  prop- 


100  E      T    BRAKE    DEFECTS 

erly.  Grit  or  scales  from  the  inside  of  the  air  pipes  will 
cut  the  seats  of  the  valves  so  they  will  leak,  and  leaks 
are  the  puzzle  of  this  brake.  Look  out  for  leaks  across 
the  gasket  between  the  distributing  valve  and  its  reservoir, 
as  they  occur  there  often.  To  locate  leaks  to  the 
atmosphere  use  soapsuds  at  the  suspected  joint.  To  locate 
the  leaks  into  the  piping  from  the  valves,  open  the  pipe 
joints  at  the  unions  between  the  valves,  air  will  come 
out  from  the  pipe  connected  to  the  defective  valve.  You 
can  then  follow  it  up  to  the  source  of  the  leak.  In  case 
of  broken  pipes  when  out  on  the  road,  if  you  understand 
the  operation  of  the  valve  there  need  be  no  trouble  in 
understanding  what  to  do  and  whether  the  brake  can  be 
still  operated.  If  you  will  remember  that  the  distributing 
valve  depends  on  the  pressure  of  air  in  the  application 
chamber  to  open  and  close  the  valves  that  control  the 
passage  to  and  from  the  brake  cylinder  it  will  make  the 
operation  of  this  valve  clear  to  you.  When  air  gets  into 
this  chamber,  whether  from  a  leak  through  either  brake 
valve,  the  slide  valve  31  or  the  gaskets,  it  will  raise  the 
pressure  there  and  apply  the  engine  brake.  Or,  if  the  air 
can  pass  out  of  this  chamber  either  the  regular  way 
through  the  brake  valves  or  leaks  in  the  pipe  connections 
the  engine  brake  will  release.  First  study  out  how  the 
air  gets  into  and  out  of  this  chamber  and  it  will  clear  up 
many  things  that  otherwise  would  puzzle  you. 

There  are  several  forms  of  the  distributing  valve  in 
service,  with  some  differences  in  their  construction  and 
operation,  and  it  is  likely  that  other  changes  will  be  made 
in  the  valve  from  time  to  time. 

38.  Q.  Describe  the  Combined  Automatic  and  Straight 
Air  Engine  and  Tender  brake. 

A.  This  brake  valve  contains  two  check  valves,  8  and 
9 — see  Figures  1  and  2 — to  admit  air  from  the  main  reser- 
voir to  the  brake  cylinders  and  9  to  exhaust  the  air  from 
the  cylinders  to  the  atmosphere.  These  valves  are  moved 
away  from  their  seats  alternately  by  the  shaft  2,  which 
when  revolved  to  the  right,  forces  valve  8  off  its  seat 


STRAIGHT    AIR    BRAKE 


101 


against  the  pressure  of  the  main  reservoir,  iir'in'a  and  the 
spring  11;  when  revolved  to  the  left  forces  the  exhaust 
valve  9  off  its  seat  against  the  pressure  of  the  spring  10 
and  the  brake  cylinder  air.  To  apply  the  brake  the  handle 
4  is  moved  to  the  right.  With  valve  8  moved  down  off  its 
seat,  main  reservoir  air  in  a  passes  through  b,  bl  and  t>- 
— see  Fig.  3 — and  out  at  x — see  Fig.  2 —  through  the  pip- 
ing leading  to  the  Double  Check  valves  and  cylinders. 
Exhaust  valve  9  at  this  time  is  on  its  seat  as  shown  in 
Fig.  2,  so  that  no  air  can  pass  out  through  c  to  the 
exhaust.  To  release  the  brake  the  handle  4  is  moved  to 
the  left,  which  allows  main  reservoir  air  valve  8  to  close 


102  DOUBLE,  CJE^Cfs    VALVE 

and  then  open  exhaust  valve  9,  jo  thai  air  in  the  cylinders 
can  pass  out  to  the  atmosphere.  When  handle  4  is  in 
mid-position,  both  valves  are  closed  so  that  they  are 
"on  lap.'' 

A  leather  washer  6  prevents  leakage  from  b  to  the 
atmosphere  when  the  brake  is  applied ;  spring  7  holds 
shaft  2  against  this  washer  when  there  is  no  compressed 
air  in  this  part  of  the  valve — see  Fig.  3. 

To  regulate  the  pressure  of  the  air  fed  from  the  main 
reservoir  to  this  valve,  a  G-6  Slide  Valve  Feed  Valve  is 
used,  located  on  the  pipe  between  the  reservoir  and  brake 
valve  and  set  to  close  at  45  pounds.  This  reducing  valve 
regulates  the  brake  cylinder  pressure  to  the  proper  amount, 
and  also  restricts  the  flow  of  air  and  assists  the  engineer 
in  making  moderate  applications. 

The  Double  Check  Valve  shown  in  Fig.  4  is  located  in 
the  pipe  between  the  triple  valve  and  the  cylinders,  in  a 
horizontal  position  so  that  it  will  not  open  or  close  by 
gravity.  The  triple  valve  is  coupled  to  one  end,  the 
straight  air  brake  valve  at  the  other.  The  brake  cylinder 
can  be  coupled  to  either  side,  as  shown,  one  side  can  be 
used  for  the  safety  valve,  or. a  driver  brake  cylinder  can 
be  coupled  to  each  side  and  the  safety  valve  located  in  the 
pipe  leading  to  the  cylinder.  Two  of  these  valves  are 
required,  one  on  the  engine  and  one  on  the  tender,  with 
a  24-inch  pipe  connecting  them  to  the  straight  air  brake 
valve,  the  same  as  the  1-inch  brake  pipe  connects  the 
triple  valve  and  automatic  brake  valve. 

Two  safety  valves  are  required,  one  for  the  engine  and 
one  for  the  tender,  set  at  53  pounds. 

When  the  straight  air  is  used  it  moves  valve  5,  Fig.  4, 
over  so  gasket  7  makes  a  tight  joint  at  b  and  the  air 
passes  through  opening  c  to  the  cylinders,  but  cannot  get 
to  the  exhaust  port  of  triple  valve.  If  automatic  is  applied, 
air  from  the  triple  valve  moves  valve  5  so  the  opposite 
gasket  makes  a  joint  at  a  and  air  passes  through  ports 
cl  to  the  cylinders,  but  cannot  pass  to  the  straight  air 
brake  valve.  Thus  you  see  the  double  check  valves  auto- 
matically connect  the  brake  cylinders  to  either  the  auto- 


DOUBLE     CHECK     VALVE 


103 


matic  or  straight  air  system  and  prevent  air  passing  out 
of  the  exhaust  port  of  one  system  while  the  other  is 
being  operated. 

When  operating  the  straight  air,  move  handle  4  over 
and  you  will  feel  the  resistance  of  valve  8;  a  little  practice 
will  enable  yon  to  calculate  the  amount  of  air  you  allow  to 
pass  into  the  cylinders  in  a  partial  application;  you  can 


TO  BRAKE  CYLINDER, 
OR    FOR  SAFETY  VALVE 
Fig.  4 


Fig.  3. 


104  OPERATING   STRAIGHT   AIR  BRAKE 

follow  up  by  admitting  additional  amounts  of  air,  till  if 
necessary,  the  brake  is  fully  applied,  of  course,  taking  care 
not  to  shock  the  cars  attached  to  the  engine  by  too  sud- 
den an  application.  If  it  is  to  be  held  fully  applied  leave 
the  valve  in  application  position,  so  as  to  feed  up  any 
leaks  that  may  reduce  the  power.  For  a  full,  quick  appli- 
cation the  valve  may  be  opened  wide,  as  the  reducing 
valve  will  stop  the  flow  of  air  from  the  main  reservoir 
when  it  reaches  the  pressure  at  which  the  reducing  valve 
is  set.  A  partial  release  can  be  obtained  by  opening  and 
closing  the  valve  9 ;  a  quick,  full  release  by  moving 
handle  4  to  exhaust  position  and  holding  valve  9  open. 

If  the  straight  air  brake  is  left  on  lap  while  the  auto- 
matic is  applied,  when  the  automatic  is  released  the  double 
check  valve  may  be  shifted  by  the  pressure  of  the  air  that 
may  get  in  the  pipe  between  the  check  and  the  straight 
air  valve,  if  the  check  valve  shifts  and  closes  the  opening 
at  b  the  brake  cylinder  air  cannot  get  out  of  exhaust  port 
of  triple,  and  thus  cause  the  driver  and  tender  brakes  to 
stick.  A  new  style  of  double  check  valve  now  in  service 
prevents  this  trouble.  When  using  automatic,  handle  4 
should  always  be  in  full  release  position,  holding  valve  0 
open.  The  automatic  brake  valve  when  not  in  use  should 
be  on  running  position  and  at '  least  10  pounds  excess 
carried  to  prevent  triple  valves  "creeping  on"  at  any  time. 

Never  apply  both  brakes  at  once  while  switching. 
When  you  use  automatic  be  sure  the  other  is  in  release 
position  first.  If  necessary  to  use  straight  air  on  top  of 
the  automatic  to  hold  the  slack  of  train,  when  the  auto- 
matic is  to  be  released,  remember  that  a  movement  of 
both  valves  to  release  is  necessary  to  let  off  the  locomotive 
brake. 

If  wheels  skid  on  a  good  rail,  test  the  safety  valves  and 
the  reducing  valve;  they  should  relieve  any  over  pressure, 
whether  from  a  .reducing  valve  allowing  too  high  a  press- 
ure, or  from  a  double  application,  that  is,  an  application 
with  the  automatic  while  the  straight  air  is  still  applied; 
this  will  give  a  higher  pressure  than  if  the  automatic 


STRAIGHT   AIR   BRAKE   PRESSURE  105 

has  set  full  first  and  is  almost  sure  to  slide  wheels;  there- 
fore must  not  be  used.  Straight  air  gives  45  pounds  only 
in  the  cylinders  at  any  time ;  if  the  automatic  is  applied  on 
top  of  this  45  pounds,  the  70  pounds  in  the  auxiliary  will 
tend  to  raise  the  cylinder  pressure  close  to  65  pounds.  The 
safety  valves  should  reduce  it  down  to  53  pounds. 

Both  safety  valves  and  the  feed  valve  should  be  tested 
at  regular  intervals  with  a  gage  to  insure  that  they 
regulate  the  pressure  properly.  There  should  be  Tees  so 
located  in  the  pipes  that  a  gage  can  be  readily  attached 
for  this  purpose. 

39.  Q.     How    should    the    automatic    brake    valve    be 
carried  when  backing  up  the  train,  or  when  expecting  the 
trainmen  to  set  brake  from  rear  end? 

A.  On  running  position;  so  the  brake  will  be  applied 
as  soon  as  brake  pipe  pressure  is  reduced,  when  brake 
valve  should  be  placed  on  lap  at  once.  This  also  applies 
to  pushing  a  snow  plow  if  brake  is  handled  from  the  plow. 
A  few  companies  require  that  the  brake  valve  be  kept  on 
running  position  all  the  time,  when  backing  up  a  train. 
There  is  some  difference  of  opinion  as  to  the  proper  posi- 
tion of  the  H-5  valve,  some  carry  it  on  holding  position 
and  use  the  independent  valve  to  release  the  locomotive 
brake.  The  H-6  valve  can  be  carried  in  running  position. 

40.  Q.     How    do    you    set    and    release    the    automatic 
brake  ? 

A.  Reducing  the  brake  pipe  pressure  operates  the  triple 
valve  to  apply  the  brake  and  restoring  the  original  press- 
ure releases  it;  this  is  the  engineer's  method.  It  can  be 
applied  from  the  train  by  opening  the  conductor's  valve,  or 
the  angle  cock  at  the  rear  of  last  air  brake  car.  Pulling 
the  hose  apart  at  the  couplings,  a  hose  bursting  or  any 
bad  leak  or  break  in  the  brake  pipe  will  set  the  brake. 
When  the  train  breaks  in  two  between  air  cars  all  air 
brakes  on  both  parts  of  the  train  that  are  cut  in  set 
instantly.  A  brake  can  be  set  on  a  car  that  is  alone  by 
opening  the  angle  cock  to  let  air  out  of  the  brake  pipe. 
In  such  a  case  the  brake  can  be  released  by  bleeding  the 


106  GRADUATED    APPLICATION 

auxiliary  reservoir.  If  a  brake  is  to  be  released  from  the 
train  the  auxiliary  pressure  is  reduced  by  bleeding  till  it 
is  lower  than  the  brake  pipe  so  the  triple  valve  will  open 
the  exhaust  port,  or  all  the  air  is  bled  out  of  both  reser- 
voir and  brake  cylinder.  Usually  the  release  spring  in 
the  brake  cylinder  will  push  the  brake  piston  back  over 
the  leakage  groove  before  the  graduating  spring  moves 
the  triple  piston  and  slide  valve  to  lap.  ' 

41.  Q.     Can    a    gradual    application    of    the    brake    be 
made,  that  is,  with  only  part  of  its  full  force? 

A.  Yes,  by  reducing  the  brake  pipe  pressure  only  a 
few  pounds,  say  live  to  seven  pounds  for  first  reduction; 
this  reduction  is  necessary  to  make  brake  piston  move  over 
leakage  groove;  a  lighter  reduction  than  five  pounds  will 
not  always  do  this;  two  to  three  pounds  at  each  of  the 
succeeding  reductions,  less  than  twenty  pounds  in  all. 

42.  Q.     Why  does  this  reduction  of  only  a  few  pounds 
in  the  brake  pipe  pressure  make  a  light  application  of  the 
brake? 

A.  With  a  light  reduction  the  triple  piston  moves 
down  slowly,  opening  the  air  valve  slowly;  the  air  from 
the  auxiliary  reservoir  passes  into  brake  cylinder  through 
graduating  valve  and  a  small  port  in  the  slide  valve;  as 
soon  as  the  auxiliary  pressure  is  a  little  lower  than  brake 
pipe  pressure,  the  brake  pipe  pressure  raises  the  piston, 
closing  the  graduating  valve  so  no  more  air  can  pass  into 
brake  cylinder,  thus  setting  the  brake  lightly.  To  illus- 
trate this,  we  will  let  out  seven  pounds  of  air,  reducing 
brake  pipe  pressure  from  70  to  63  pounds,  that  leaves  70 
pounds  above  triple  piston,  which  moves  the  triple  piston 
down  towards  the  lower  pressure,  opening  graduating 
valve  7  first;  then  moving  slide  valve  3  so  that  air  can 
pass  through  it;  when  enough  air  has  gone  into  the 
cylinder  to  reduce  the  auxiliary  pressure  below  63  pounds, 
the  brake  pipe  pressure  moves  the  piston  towards  the 
lower  auxiliary  pressure,  closing  graduating  valve; 
another  reduction  produces  the  same  effect,  each  time 
setting  brake  tighter  till  pressures  equalize.  The  piston 


FULL   SERVICE   APPLICATION  107 

moves  the  main  slide  valve  at  the  first  reduction,  but  only 
opens  and  closes  the  graduating  valve  at  the  following 
reductions  till  a  full  application  is  made. 

43.  Q.     How  much  do  you  reduce  the  brake  pipe  press- 
ure to  make  a  full  service  application  of  the  brake  if  the 
piston  travels  are  the  proper  length?     Why  does  a  reduc- 
tion of  twenty  pounds  set  the  brake  "full  on?" 

A.  About  20  pounds,  or  from  70  pounds  down  to  50, 
or  until  the  auxiliary  pressure  has  equalized  with  brake 
cylinder. 

If  the  brake  is  in  good  order,  with  a  piston  travel 
of  eight  inches,  a  reservoir  pressure  of  70  pounds  will 
fill  the  brake  cylinder  and  equalize  in  both  at  50  pounds, 
that  will  leave  50  pounds  on  top  of  triple  piston.  If  the 
pressure  on  the  brake  pipe  side  or  under  the  triple  piston 
is  any  less  than  .50  pounds,  the  piston  will  stay  down  and 
hold  the  air  valve  open  and  pressures  must  equalize. 
One  pound  less  will  hold  it  down  as  well  as  any  amount. 
When  it  has  equalized,  no  more  air  will  pass  from  aux- 
iliary to  brake  cylinder,  pressure  on  brake  piston  will  not 
rise  above  50  pounds,  and  brake  cannot  be  set  tighter. 
Any  reduction  of  brake  pipe  pressure  that  leaves  it  lower 
than  auxiliary  pressure  will  set  the  brake  tight.  If  a  re- 
duction of  20  pounds  opens  the  air  valve  and  holds  it 
open,  any  further  reduction  will  not  produce  any  effect  on 
it,  and  so  far  as  that  brake  is  concerned  is  only  a  waste  of 
air,  which  must  be  supplied  from  main  reservoir  when 
you  want  to  release  brake.  If  any  check  valves  in  quick- 
action  triples  leak,  a  reduction  in  brake  pipe  pressure 
below  brake  cylinder  pressure  will  let  the  brake  leak  off 
through  this  check  into  brake  pipe. 

44.  Q.     What    is    necessary   to    have   brakes    set    alike, 
with  same  reduction  of  brake  pipe  pressure  and  release  at 
same   time,    with    same    increase   of   brake   pipe   pressure? 

A.  1st.  The  auxiliary  pressures  must  all  be  the  same 
to  move  triples  down  towards  the  same  reduced  brake 
pipe  pressure.  For  example,  if  one  auxiliary  has  70 
pounds,  another  60,  a  reduction  of  brake  pipe  pressure 


108  QUICK-ACTION    TRIPLE 

below  70  will  set  the  first  brake,  but  it  takes  a  reduction 
of  below  60  to  set  the  other  one.  2d.  All  piston  travels 
must  be  the  same,  for  with  a  20  pound  reduction  a  short 
travel  equalizes  at  a  less  reduction  with  a  higher  pressure 
than  a  long  travel.  When  brake  pipe  pressure  is  increased, 
triple  controlling  brake  with  long  travel  will  release  first 
as  the  auxiliary  pressure  is  lowest.  Thus,  brake  with 
long  travel  equalizes  last  with  lowest  piston  pressure  and 
lets  go  first.  3d.  That  all  triples  and  brake  pistons  are 
in  good  order  and  no  leaks.  4th.  That  the  main  reser- 
voir pressure  and  volume  are  sufficient  to  move  all  triples 
to  release  quickly. 

45.  Q.  What  is  the  difference  between  the  plain  engine 
triple  valve  and  the  car  or  quick-action  triple?  Why  will 
not  the  plain  triple  do  as  well  on  a  long  train? 

A.  A  plain  triple  gets  all  its  supply  of  air  to  set  the 
brake  from  the  auxiliary  reservoir  only;  the  quick-action 
triple  gets  it  all  from  the  auxiliary  on  a  service  applica- 
tion; when  used  with  emergency  it  gets  air  from  both 
train  pipe  and  auxiliary.  With  a  long  train  equipped  with 
plain  triples  it  takes  some  seconds  to  reduce  the  brake 
pipe  pressure  at  last  car  and  operate  the  last  triple;  the 
pressure  in  brake  pipe  is  reduced  slowly  on  last  cars, 
which  makes  them  set  gradually;  the  brake  pipe  reduction 
is  made  at  the  engine  only.  The  quick  action  triple  has 
two  separate  actions ;  in  one  a  service  application  operates 
only  the  plain  part  of  it;  in  the  other,  plain  and  quick 
action  parts  are  operated  at  once.  A  quick  action  triple  is 
not  always  needed  on  an  engine  or  tender,  as  they  are  so 
close  to  the  brake  valve  that  they  operate  quickly  enough. 
In  an  emergency  application  the  quick-action  triple  allows 
some  of  the  brake  pipe  air  to  escape  at  the  triple  so  that 
the  brake  pipe  pressure  is  suddenly  reduced  at  this  triple; 
this  also  operates  the  next  triple  quick-action,  which  re- 
duces the  brake  pipe  pressure  still  more,  so  that  all  the 
triples  act  quicker  than  when  the  reduction  is  made  at 
the  brake  valve,  and  all  the  brakes  are  set  at  nearly  the 
same  instant.  Thus  there  is  less  shock  to  the  rear  cars 


EMERGENCY     APPLICATION  109 

of  a  full  air  brake  train,  as  the  action  of  the  triples 
travels  from  one  to  the  other  faster  than  the  slack  can 
run  up  from  car  to  car. 

46.  Q.     What   is   the   emergency  or   quick   application? 

A.  If  the  brake  pipe  pressure  is  suddenly  reduced  at 
the  first  application  10  pounds  or  more,  at  the  quick- 
action  triple,  so  the  graduating  valve  cannot  reduce  the 
auxiliary  pressure  at  the  same  rate,  auxiliary  pressure 
will  move  piston  by  the  service  position,  the  emergency 
part  of  the  triple  valve  is  brought  into  action,  opening  a 
large  port  in  the  triple  so  the  air  goes  from  the  brake 
pipe  direct  into  the  brake  cylinder,  not  only  setting  the 
brake  quick-action,  but  also  reducing  the  brake  pipe 
pressure  suddenly  at  that  point,  instead  of  all  the  air 
having  to  go  clear  to  brake  valve  to  escape  and  reduce 
pressure.  This  sudden  reduction  sets  the  next  triple  in 
the  same  manner,  which  sets  the  next  one,  and  so  on  to 
the  last  car;  its  action  from  one  car  to  another  is  so  quick 
that  even  on  a  long  train  it  seems  to  catch  all  at  once. 
When  a  quick-action  triple  takes  air  from  the  brake  pipe 
and  sets  the  next  triple  quick-action,  it  also  takes  air 
from  its  auxiliary  through  a  small  port  s>  after  the  brake 
pipe  has  equalized,  so  the  full  application  is  made  at  60 
pounds,  about  10  pounds  more  than  the  piston  pressure 
in  full  service  application. 

If  at  the  head  end  of  train  there  are  four  cars  with 
the  triples,  cut  out  at  the  cross-over  cocks;  or  four  cars 
with  brake  pipe  only,  the  reduction  of  brake  pipe  pressure 
at  the  fifth  car  will  be  so  gradual  that  it  will  not  work 
quick-action;  it  takes  a  sudden  reduction  right  at  the 
triple  to  get  the  quick  action.  When  there  are  only  two 
or  three  cars  behind  these  cut-out  triples,  the  small  volume 
of  their  brake  pipe  will  assist  in  having  the  quick-action 
jump  over  the  cut  out  ones.  At  the  rear  end  more  than 
four  cars  can  be  cut  out  and  get  the  quick-action  as  the 
"dead  end"  of  the  brake  pipe  will  help  to  make  a  sudden 
reduction  on  the  last  cars. 

A  sudden  reduction  of  brake  pipe  pressure  which  will 


110 


EMERGENCY     APPLICATION 


pull  the  triple  piston  down  hard  enough  to  compress  the 
graduating  spring  and  let  piston  make  a  full  travel  will 
open  the  large  air  port  in  plain  triple  valve,  so  brake  will 
set  somewhat  quicker,  but  does  not  set  with  any  higher 
piston  pressure. 

47.  Q.  Explain  the  operation  of  the  quick-action  triple 
when  used  on  the  "emergency." 

A.  A  sudden  reduction  in  the  brake  pipe  pressure 
right  at  the  triple  must  be  made,  so  the  triple  piston  will 
make  a  full  stroke  and  open  the  emergency  port  in  seat 


This  cut  shows  the  quick-action 
triple  in  emergency  position.    Port  / 
registers  with  the  notch  in  side  of 
slide  valve  or  the  "removed  corner" 
of  slide  valve,  which  is  not  shown  in 
cut.      Auxiliary  air  passes   through 
this  notch  under  port  z  into  t  on  emergency 
piston  8.    Poits  z  and  /  are  beside  each  other, 
but  no  air  passes  from  port  z  into  /. 

QUICK -ACTION  TRIPLE  VAI/VE— EMERGENCY  POSITION. 


EMERGENCY      APPLICATION  111 

under  slide  valve,  which  will  admit  the  auxiliary  pressure 
over  the  emergency  piston  8.  This  in  turn  pushes  the 
emergency  or  rubber-seated  valve  10  off  its  seat,  and  the 
brake  pipe  air  can  then  go  direct  to  brake  cylinder  through 
large  port  C,  raising  the  brake  pipe  check  valve  15  to  do 
this.  As  soon  as  the  brake  pipe  and  brake  cylinder  press- 
ures have  equalized,  the  check  15  seats  itself,  and  a  spring 
in  this  check  valve  pushes  the  rubber-seated  valve  10  up 
against  its  seat  as  soon  as  the  auxiliary  and  brake  cylinder 
pressures  are  nearly  equalized.  At  the  same  time  that 
brake  pipe  air  is  passing  into  the  cylinder,  the  air  from 
the  auxiliary  is  also  going  through  a  small  port  in  the 
end  of  slide  valve  3.  This  port  is  made  very  small  to 
give  the  brake  pipe  air  a  chance  to  equalize  into  the  brake 
cylinder  first,  then  the  auxiliary  pressure  equalizes  with 
the  brake  cylinder  afterwards,  at  about  60  pounds.  The 
emergency  valve  10  is  used  to  hold  the  brake  pipe  air 
out  of  the  brake  cylinder,  therefore  in  quick-action  it 
must  be  moved  off  its  seat  against  the  brake  pipe  press- 
ure; this  is  done  only  when  triple  piston  makes  a  fulf 
stroke  suddenly.  If  it  moves  down  slowly,  the  graduating 
valve  will  allow  air  to  pass  from  auxiliary  into  brake 
cylinder  before  emergency  port  is  opened,  and  reduce 
the  auxiliary  pressure  as  fast  as  the  brake  pipe  pressure 
falls,  so  graduating  spring  will  have  power  to  prevent  a 
full  stroke  of  piston. 

48.  Q.  Can  you  get  the  emergency  action  of  the  quick- 
action  triple  while  brakes  are  set  with  a  service  applica- 
tion? 

A.  Not  unless  they  are  set  with  a  light  application. 
The  pressure  in  auxiliary  and  brake  pipe  must  be  con- 
siderably higher  than  in  the  brake  cylindejr,  or  the 
emergency  piston  will  not  move  valve  10  off  its  seat,, 
nor  will  check  15  raise  to  allow  air  to  pass  through. 
Then,  if  a  partial  service  application  has  been  made,  the 
graduating  valve  can  open  first,  which  reduces  the  aux- 
iliary pressure  some  and  retards  the  full  stroke  of  the 
piston  a  little  in  opening  the  emergency  port.  Even  if 


112  EMERGENCY    APPLICATION 

all  these  emergency  valves  operate  after  a  moderate 
service  application,  only  a  very  little  air  will  pass  through 
them,  not  enough  to  affect  the  triples  behind  it,  or  raise 
the  pressure  in  cylinder  very  much.  See  Q.  111. 

49.  Q.     Is   it  practicable   to   attempt   to   get  the   emer- 
gency   action    of    the    brake    by    suddenly    recharging    the 
brake  pipe  for  one  or  two  seconds  and  then  opening  the 
direct  application  port  wide? 

A.  No.  The  triple  piston  will  not  move  till  you  have 
reduced  the  brake  pipe  pressure  a  little  lower  than  the 
auxiliary  pressure,  and  no  air  can  pass  into  the  brake 
cylinder  from  either  brake  pipe  or  the  auxiliary  till  piston 
moves  and  opens  the  valves.  By  this  movement  you  will 
partially  release  some  of  the  brakes  and  may  get  a  lighter 
service  application  the  second  time  than  you  had  at  first 
Don't  try  it.  Unless  you  have  time  to  recharge  auxiliaries 
to  70  pounds,  hang  on  to  what  you  have. 

50.  Q.    Is  it  safe  to  try  and  retain  air  in  a  brake  pipe 
in  the  emergency  application,  and  why  not? 

A.  It  is  not  safe  as  a  general  rule.  In  an  emergency 
when  life  or  property  are  in  danger,  you  must  act  quickly, 
The  point  is  to  get  stopped  dead  as  soon  as  possible,  and 
see  about  getting  started  afterwards.  An  emergency  appli- 
cation is  the  last  resort  and  you  must  get  it  when  you 
need  it.  If  you  do  not  let  nearly  all  the  air  out  of  a  long 
brake  pipe,  some  of  the  triples  will  not  act  quick  enough. 
If  three  or  four  triples  are  cut  out,  or  there  are  three  or 
four  plain  triples  close  together  at  the  head  end  of  the 
train,  the  quick-action  will  not  catch  behind  them  and 
all  the  air  must  be  let  out  at  head  end  of  train  to  reduce 
the  pressure  as  quickly  as  possible.  A  full  reduction  of 
20  pounds  is  necessary  to  set  the  plain  triples  on  engine 
and  tender  so  these  brakes  will  do  their  full  share.  With 
a  double  header  it  is  generally  necessary  to  let  the  air 
out  at  brake  valve  of  rear  engine  to  catch  the  quick- 
action  on  the  train.  With  a  full  train  of  quick-action 
triples  a  sudden  reduction  of  25  or  30  pounds  at  the 
engine  will  catch  them  all  and  leave  considerable  air  in 


QUICK-ACTION   TRIPLE   DEFECTS  113 

the  brake  pipe,  so  you  can  release  and  back  up  out  of 
the  other  tram's  way  if  the  brake  stops  you  in  time.  This 
is  the  only  special  exception  to  the  general  rule.  It  is 
easy  to  hold  part  of  the  air  when  making  tests  or  in  the 
instruction  car;  but  when  you  think  some  one  is  going 
to  get  killed,  it  is  not  quite  as  easy  as  clear  over  to  full 
emergency. 

51.  Q.     How  does  the  quick-action  triple  operate  on  a 
short  train,  if  graduating  pin  is  broken?     Or  the  graduat- 
ing ports  gummed  up? 

A.  With  the  emergency  on  a  light  service  application. 
If  the  graduating  pin  is  broken,  the  graduating  valve  will 
be  held  on  its  seat  by  auxiliary  pressure,  and  the  emer- 
gency port  is  the  first  one  to  open. 

If  the  graduating  valve  is  gummed  up  or  dirty  so  the 
air  can  not  flow  past  it  properly,  the  triple  will  work  with 
emergency  when  you  make  a  moderate  service  application. 
With  a  long  train  the  emergency  port  is  opened  so  gradu- 
ally that  the  air  can  get  past  the  emergency  piston  and  go 
to  the  cylinder  without  moving  the  emergency  piston. 

52.  Q.     If    while    making   a    moderate    service    applica- 
tion your  brakes  would  "fly  on"  and  at  the  same  time  the 
air  would   stop   running   for   a  moment   from   brake   pipe 
exhaust  and  then  begin  again,  where  would  you  look  for 
the  trouble? 

A.  In  one  of  the  quick-action  triples.  This  action  of 
the  brake  valve  shows  that  one  of  the  triples  is  working 
quick-action  only,  in  advance  of  the  rest,  even  with  a 
service  application.  When  the  triple  works  quick-action, 
it  takes  some  air  from  the  brake  pipe,  reducing  the  press- 
ure so  the  equalizing  piston  seats  for  an  instant.  At  the 
same  time  the  black  hand  takes  a  sudden  drop  for  an 
instant.  Probably  the  graduating  pin  is  broken,  although 
a  broken  graduating  pin  in  service  is  very  rare.  If  the 
graduating  spring  22  has  been  left  out  it  is  very  apt  to 
cause  quick-action.  If  the  triple  piston  or  slide  valve  is 
gritty  or  badly  gummed  so  it  does  not  move  freely,  it  will 
cause  this  trouble. 


114  QUICK-ACTION    TRIPLE    DEFECTS 

If  the  graduating  valve  or  its  ports  are  gummed  up  so 
that  the  air  cannot  flow  past  it  out  of  auxiliary  to  equalize 
the  pressures  as  fast  as  it  flows  out  of  brake  pipe,  this 
triple  will  be  sure  to  work  quick  action.  A  quick-action 
triple  that  needs  cleaning,  or  has  the  graduating  ports 
defective  in  any  way,  is  liable  to  work  quick-action  with 
a  moderate  service  reduction.  If  the  brake  pipe  exhaust 
elbow  is  gone  from  the  brake  valve  it  will  allow  so 
sudden  reduction  of  brake  pipe  pressure  that  the  triples' 
will  work  quick-action  on  a  very  short  train. 

Improper  handling  of  the  brake  valve  will  also  cause 
triple  valves  to  go  into  quick  action  with  a  service  re- 
duction. With  a  very  long  train  it  takes  quite  a  few 
seconds  to  have  the  reduction  made  at  the  brake  valve 
felt  on  the  rear  car.  If  you  have  overcharged  the  head 
end  by  full  release  position  for  fifteen  or  twenty  seconds 
and  then  begin  a  service  application,  air  is  still  feeding 
into  the  rear  triples ;  this  makes  a  reduction  at  the  rear 
end  and  the  brake  valve  one  on  the  head  end,  the  triples 
ahead  of  the  middle  of  the  train  cannot  keep  up  and 
go  into  quick  action. 

To  locate  one  of  these  defective  triples,  close  some  of 
the  angle  cocks  so  as  to  use  not  over  ten  cars  at  a  time, 
and  make  a  moderate  reduction,  say  five  pounds,  then 
make  another  of  five  more.  If  the  brakes  work  quick- 
action  you  can  be  certain  the  defective  triple  is  on  one  of 
these  cars.  After  recharging,  set  the  brake  again  with 
about  seven  pounds  reduction,  and  note  which  brake  has 
not  set  at  all.  Cut  this  one  out  and  make  another  test, 
which  will  show  if  you  have  the  right  one.  If  you  do 
not  find  it  in  the  first  set  of  ten  cars  tried,  cut  in  some 
more  and  try  them.  The  disabled  triple  will  not  always 
set  at  the  first  reduction,  and  will  work  quick-action  at 
the  second  one :  it  is  more  apt  to  give  trouble  in  a  short 
train  than  in  a  long  one. 

53.  Q.  If  with  a  quick-action  triple,  the  brake  should 
refuse  to  release,  but  kept  blowing  from  the  exhaust  port 


QUICK-ACTION    TRIPLE   DEFECTS  115 

or  pressure  retainer,  what  would  be  the  matter  and  what 
would  you  do? 

A.  The  emergency  valve  10  was  likely  held  off  its 
seat  or  was  worn  out  and  leaked  badly.  If  out  on  the 
road  and  valve  would  not  quit  leaking  after  a  few  emer- 
gency applications,  would  cut  out  that  brake.  If  the 
gasket  between  the  triple  valve  and  cylinder  head  on  a 
passenger  brake  or  next  the  reservoir  on  a  freight  brake 
had  blown  out,  it  would  let  auxiliary  reservoir  air  into 
exhaust  and  the  blow  would  soon  be  down  to  the  capacity 
of  the  feed  port  in  triple  valve.  A  small  leak  past  the 
emergency  valve  when  the  brake  is  set  will  soon  equalize 
the  brake  cylinder  and  brake  pipe  pressures.  With  a 
sticky  triple  this  brake  might  not  release  with  increase  of 
brake  pipe  pressure  and  wheels  be  skidded.  Better  cut 
out  such  a  brake  and  bleed  it. 

54.  Q.  Describe  tthe  construction  and  operation  of  the 
Quick  Service  Triple  Valve,  Type  K. 

A.  The  quick  service  triple  valve  shown  in  the  next 
ilUistration  is  similar  to  the  ordinary  qnick-action  triple 
in  use  for  many  years,  but  has  some  additional  features. 
There  is  an  additional  air  port  y  leading  from  the 
chamber  Y  between  the  brake  pipe  check  12  and  the 
emergency  valve  10,  up  through  the  triple  body  to  the 
slide  valve  bushing  at  c.  This  port  c  is  covered  by  the 
slide  valve  so  any  air  passing  through  port  c  must  also 
pass  through  a  port  in  the  slide  valve  to  get  any  farther. 
The  graduating  valve  7  is  a  small  flat  valve  with  a  cavity 
v  in  its  face,  this  valve  rides  on  the  back  of  the  slide  valve 
3  and  moves  each  time  piston  4  does.  There  is  some  lost 
motion  between  the  shoulders  of  the  piston  stem  and  the 
ends  of  slide  valve  3,  so  the  piston  can  move  this  distance 
without  moving  valve  3,  this  allows  the  piston  to  move 
and  close  the  feed  port  i  as  well  as  open  and  close  the 
ports  under  the  graduating  valve  without  moving  slide 
valve  3.  On  the  reservoir  end  of  the  triple  is  attached  a 
cage  29,  containing  a  "retarded  release"  stem  31  and  its 
spring  33.  The  later  type  of  K  triple  is  shown  here,  and 


116 


K    TYPE    TRIPLE    VALVE 


below  the  triple  is  shown  the  first  style  of  release  stem 
and  spring.  A  small  pin  34  prevents  stem  31  moving 
too  far  in  the  cage  when  taken  off.  There  was  no, feed 
groove  in  the  shoulder  of  piston  4  where  it  rests  against 
the  slide  valve  bushing  when  at  its  extreme  travel  in 
release  position  in  the  first  K  triples,  so  that  in  this  posi- 
tion, air  passing  through  feed  port  *  could  not  get  into 
the  auxiliary.  The  later  ones  have  a  groove  in  this 
shoulder.  When  the  piston  and  slide  valve  are  in  free 
release  position  the  stem  31  and  spring  33  are  in  normal 
position — not  compressed — the  exhaust  port  in  slide  valve 
3  is  wide  open  and  the  feed  ports  open  so  brake  pipe  air 
can  equalize  to  the  auxiliary.  In  the  triples  used  with 
10-inch  brakes  and  larger  ones,  there  is  also  a  feed  port 

735    3  6 


29 

TO  AUXILIARY 
RESERVOIR 


20 


21 


12  26 


OPERATION    OF    K    TRIPLE  117 

through  the  slide  valve  that  is  open  in  free  release.  There 
is  a  small  feed  port  through  the  slide  valve  that  is  open 
only  in  retarded  release  position  which  charges  the  aux- 
iliary very  slowly.  The  feed  port  i  around  the  piston 
is  the  same  size  in  all  quick-service  triples,  so  most  of 
the  air  in  the  large  triples  passes  through  the  feed  port 
through  the  slide  valve.  After  the  auxiliary  has  charged 
to  standard  pressure,  which  we  will  assume  is  70  pounds, 
a  moderate  brake  pipe  reduction  will  move  the  piston  4 
to  the  right  following  the  reduction.  This  movement  first 
closes  feed  port  i  and  moves  the  graduating  valve  7  on 
the  back  of  the  slide  valve  3  to  close  feed  port  and  open 
the  supply  ports  under  it.  The  slide  valve  then  moves, 
first  closing  the  exhaust  port  and  next  opens  the  service 
ports  in  valve  3  to  the  ports  in  its  seat.  Auxiliary  air 
then  flows  to  the  cylinder  through  port  r.  At  the  same 
time  brake  pipe  air  from  chamber  Y  flows  through  port 
y,  a  port  through  slide  valve  3,  the  cavity  of  the  graduat- 
ing valve  7  and  ports  in  slide  valve  3  into  port  t  in  the 
seat,  and  thence  around  the  emergency  piston — which  is 
not  an  air  tight  fit — into  X  and  the  cylinder.  This  small 
amount  of  brake  pipe  air  passing  to  the  cylinder  is  not 
sufficient  to  cause  an  emergency  reduction,  but  causes  the 
next  triple  to  operate  more  certainly  and  thus  applies 
all  brakes  in  a  train  in  less  time  than  when  the  entire 
brake  pipe  reduction  is  made  at  the  brake  valve.  The 
brake  pipe  air  passing  to  the  cylinder  in  a  service  applica- 
tion increases  the  pressure  there  so  that  a  five-pound 
reduction  in  brake  pipe  and  auxiliary  will  give  about 
14  pounds  in  the  cylinder  as  well  as  applying  the  quick- 
service  triples  in  less  time  from  front  to  rear  of  train. 
The  air  from  the  brake  pipe  also  tends  to  give  a  higher 
pressure  with  long  piston  travel  than  with  the  old  triples 
taking  air  from  the  auxiliary  only. 

On  account  of  the  arrangement  and  size  of  the  service 
ports  the  quick-service  triples  are  not  as  liable  to  go  into 
undesired  quick  action  as  the  older  form.  When  in  quick- 
service  position  the  ports  are  only  open  a  portion  of  their 


118  OPERATION   OF   K  TRIPLE 

full  size  to  reduce  the  auxiliary  pressure  as  fast  as  brake 
pipe  pressure  is  ordinarily  reduced  at  the  brake  valve.  If 
the  triple  piston  moves  over  enough  to  compress  the 
graduating  spring  22  a  little,  the  service  ports  will  open 
wide;  this  reduces  auxiliary  pressure  so  fast  that  the 
piston  will  not  go  to  emergency  position  for  a  moderate 
reduction  unless  it  is  defective.  When  the  brake  valve  is 
placed  in  full  release  and  the  brake  pipe  at  the  head  of 
the  train  charged  much  higher  than  the  auxiliary  press- 
ures there,  the  quick-service  triples  there  will  move  past 
free  release  position  compressing  the  stem  31  and  spring 
33  and  the  slide  valve  exhaust  cavity  will  be  moved  far 
enough  so  the  wide  open  port  of  this  cavity  will  be 
beyond  the  exhaust  port  and  the  small  part  of  the  exhaust 
cavity  will  be  in  register  with  the  port.  This  causes  the 
air  to  exhaust  from  the  brake  cylinder  very  slowly  and 
the  quick-service  triples  at  the  head  end  that  have  the 
high  brake  pipe  pressure  hold  their  brakes  set  some 
seconds  longer  than  when  in  free  release  position.  As 
the  brake  pipe  pressure  reduces  farther  back  in  the  train 
until  it  is  not  enough  higher  than  the  auxiliary  to  move 
the  triple  piston  to  retarded  release  position  against  the 
resistance  of  spring  33,  the  triples  will  all  move  to  free 
release  position  as  fast  as  the  increase  of  brake  pipe 
pressure  reaches  them.  On  a  fifty-car  train  equipped  with 
the  quick-service  triples,  about  one-third  of  them,  or 
fifteen  to  twenty  will  go  to  retarded  release  and  those 
next  will  release  quickly.  This  tends  to  release  the 
middle  and  rear  cars  of  a  long  train  before  the  cars  next 
the  engine  are  fully  released,  as  the  head  brakes  are 
retarded,  the  whole  train  will  release  at  about  the  same 
time,  and  thus  prevent  the  slack  running  out  and  break- 
ing trains  in  two  or  more  parts  when  releasing  brakes  at 
a  slow  speed.  To  get  the  retarded  exhaust  of  quick-service 
triples  when  the  entire  train  is  not  equipped  with  them, 
these  triples  should  be  next  the  engine.  When  at  the 
rear  they  do  not  retard  the  release  any  more  than  the 
ordinary  quick-action  triple. 


TYPE    L    TRIPLE   VALVE  119 

55.  Q.     Describe    the    Westinghouse    Type    L    Triple 
Valve. 

A.  The  Westinghouse  L  triple  valve  is  designed  for 
high  duty  passenger  service,  it  is  pipeless,  that  is,  all  air 
pipe  connections  are  made  at  the  pressure  head  to  which 
the  triple  is  bolted;  it  uses  two  reservoirs;  one  the 
ordinary  size  for  that  brake  cylinder  and  a  supplementary 
reservoir  about  twice  the  volume  of  the  service  auxiliary. 
In  case  this  supplementary  is  not  to  be  used  when  other 
cars  in  the  train  do  not  have  it,  a  cock  cuts  it  out  from 
the  triple  valve,  this  cuts  out  the  graduated  release 
feature  and  the  very  high  pressure  with  quick  action.  The 
L  triple  is  a  quick-service  and  a  quick-action  valve,  the 
quick-service  feature  has  been  explained  in  connection 
with  the  K  triple,  and  the  quick-action  also,  we  need  not 
repeat  all  of  it  here,  and  it  is  understood  that  the  student 
is  familiar  with  the  action  of  the  ordinary  quick-action 
triple.  This  triple  does  not  have  the  retarded  release 
through  a  small  exhaust  cavity  that  the  K  triple  has, 
therefore  does  not  use  a  retarded  release  spring,  the  ex- 
haust cavity  is  in  the  graduating  valve,  and  is  of  the 
proper  size  to  exhaust  the  brake  cylinder  air  in  the 
standard  time.  The  exhaust  valve  is  under  control  of 
the  engineer,  who  by  changes  in  the  brake  pipe  pressure 
and  the  aid  of  the  supplementary  reservoir,  can  allow  all 
the  brake  cylinder  air  to  pass  out  freely,  or  hold  it  back 
and  reduce  the  cylinder  pressure  a  little  at  a  time  till 
down  to  nothing;  by  the  control  of  the  exhaust  you  can 
have  a  moderate  cylinder  pressure  at  the  instant  the  stop 
is  made. 

Two  sectional  views  of  the  actual  valve,  a  side  eleva- 
tion and  an  end  elevation  and  a  diagrammatic  view  of 
the  valve  in  full  release  and  charging  position  are  shown. 

In  release  position,  or  when  running  between  stations 
both  reservoirs  charge  at  the  same  time  and  to  the  same 
pressure  through  the  L  triple.  There  is  the  usual  feed 
groove  i  in  the  cylinder  bushing  to  allow  air  from  the 
brake  pipe  to  pass  around  the  triple  piston;  it  is  a  small 


TYPE    L    TRIPLE    VALVE 


FULL  RELEASE  AND  CHARGING   POSITION. 


one,  more  to  keep  the  brake  pipe  and  auxiliaries  equalized 
after  charging  than  to  do  much  of  that  work.  There  is 
a  charging  port  /  through  the  slide  valve;  open  in  release 
position  only,  that  connects  with  cavity  Y  above  the 
brake  pipe  check  15 ;  air  can  pass  by  check  15  and  go 
through  the  slide  valve  3  to  the  reservoirs,  but  check  15 
prevents  it  getting  back  to  the  brake  pipe  during  a  reduc- 
tion. When  a  service  application  begins,  this  charging 
port  in  slide  valve  3  is  first  closed  as  well  as  the  port  k 
leading  to  the  supplementary  through  x,  so  no  air  can  get 


OPERATION    OF    L    TRIPLE  121 

out  of  there,  air  from  the  service  auxiliary  only  is  used 
in  a  service  application,  supplementary  air  remains  bottled 
up  till  the  triple  goes  to  release  position,  when  this  large 
volume  of  air  at  standard  pressure  will  quickly  equalize 
with  the  service  auxiliary  at  close  to  the  standard  press- 
ure, even  before  the  brake  cylinder  air  has  escaped;  this 
makes  a  quick  recharge  from  the  supplementary  to  the 
service  auxiliary.  If  90  pounds  is  carried,  after  a  full 
service  application  the  service  auxiliary  will  have  70 
pounds,  and  the  90  pounds  in  the  supplementary  will 
equalize  in  both  of  them  at  over  83  pounds,  air  from  the 
brake  pipe  will  soon  put  the  other  6  pounds  in. 

Referring  to  the  diagrammatic  view,  all  the  air  ports, 
passages  and  cavities  in  the  valve  and  seat  are  shown ; 
something  that  cannot  be  done  in  the  view  of  the  actual 
valve  as  many  of  the  ports  cannot  be  made  to  show  in  a 
correct  sectional  view.  Air  from  the  brake  pipe  enters 
at  the  lowest  passage  through  a,  e  and  g  to  h,  forces  the 
triple  piston  4  to  release  and  charging  position,  if  not 
already  there,  and  passes  around  the  triple  piston,  through 
port  *  into  R  and  the  auxiliary  reservoir.  Air  also  passes 
through  port  k  in  slide  valve  3  and  x  to  the  supplementary 
so  it  charges  at  the  same  time  as  the  service  auxiliary. 
Brake  pipe  air  raises  check  15  and  goes  through  port  y 
in  the  body  of  the  valve  and  its  seat,  thence  through  port 
y  in  slide  valve  3  to  R,  so  air  is  passing  into  R  from  two 
sources.  Port  j  is  larger  in  the  large  triples  than  in  the 
small  ones,  but  feed-groove  i  is  the  same  size  in  all  of 
them.  Any  air  that  may  be  in  the  brake  cylinder  will 
pass  through  C,  r,  n,  in  valve  3,  then  through  cavity  w  in 
graduating  valve  7  into  port  m,  and  finally  into  P,  the 
final  exhaust.  You  will  note  that  exhaust  air  must  pass 
through  a  cavity  in  graduating  valve  7,  this  will  explain 
why  a  movement  of  the  graduating  valve  will  open  and 
close  the  exhaust,  t  is  the  emergency  port  through  which 
auxiliary  air  passes  in  over  piston  8  when  slide  valve  3 
is  back  in  emergency  position.  There  are  two  pistons  in 
this  triple  that  operate  only  in  an  emergency  application, 


122  OPERATION     OF    L    TRIPLE 

piston  8  that  does  the  same  work  as  piston  8  in  the 
ordinary  quick-action  triple  and  piston  25,  called  the  by- 
pass piston,  its  duty  is  to  open  by-pass  valve  27  to  allow 
air  in  the  supplementary  to  equalize  with  the  service 
auxiliary  in  an  emergency  application.  This  piston  is 
shown  at  the  top  in  the  actual  triple.  During  a  service 
application  the  auxiliary  pressure  remains  equalized  on 
both  sides  of  piston  25  so  it  does  not  move.  In  an 
emergency  application  slide  valve  3  moves  back  far 
enough  so  port  c  registers  with  d  in  the  slide  valve,  this 
opens  a  communication  between  f  on  the  inside  of  piston 
25,  through  c,  d,  m  and  r  to  the  brake  cylinder;  auxiliary 
pressure  in  B  forces  it  over  and  opens  valve  27; 
this  allows  supplementary  air  to  flow  to  the  auxiliary 
and  equalize  at  very  nearly  the  standard  auxiliary  press- 
ure. If,  at  a  service  application,  an  emergency  arises,  a 
sudden  reduction  of  brake  pipe  pressure  at  the  brake 
valve  will  put  the  L  triples  into  the  emergency  position, 
the  by-pass  valve  will  be  opened  and  the  supplementary 
air  will  pass  into  the  brake  cylinder  and  service  auxiliary 
giving  a  high  braking  pressure,  which  the  safety  valve 
will  hold  till  released  the  regular  way.  Port  b  connects 
with  safety  valve  33  in  release  and  all  service  positions 
so  the  safety  valve  can  blow  down  cylinder  pressure  to 
its  adjustment  at  ordinarily  62  pounds.  In  an  emergency 
application  cavity  q  travels  past  port  r  so  the  brake 
cylinder  is  cut  off  from  the  safety  valve  and  there  is  no 
escape  of  air  at  the  safety  valve  in  an  emergency  applica- 
tion, all  the  air  is  held  in  the  cylinder  till  the  brake  is 
released  the  regular  way. 

In  a  graduated  service  application  there  are  two  posi- 
tions of  piston  4  and  slide  valve  3,  the  first  one  is  quick- 
service  position;  in  this,  port  o  in  valve  3  is  brought  in 
register  with  port  y  in  the  seat,  so  air  passing  check  15 
can  flow  through  y  and  o,  graduating  valve  7  being  moved 
back  at  that  time  air  from  o  will  pass  through  the  small 
cavity  v  in  graduating  valve  7,  through  the  small  port 
into  cavity  q  and  thence  to  C  and  the  brake  cylinder,  this 


OPERATION     OF     L     TRIPLE  123 

makes  a  gradual  brake  pipe  reduction  at  the  triple  and 
starts  the  other  triples  in  the  rear  of  it,  to  service  position 
quicker  than  the  brake  valve  reduction  would.  Port  2 
in  slide  valve  3  has  been  brought  in  register  with  r  in 
the  seat,  graduating  valve  7  having  uncovered  z  at  the 
top,  auxiliary  air  also  flows  to  the  cylinder  at  the  same 
time  air  from  the  brake  pipe  passes  in.  As  soon  as  the 
auxiliary  pressure  is  a  little  lower  than  that  of  the  brake 
pipe  and  the  reduction  at  the  brake  valve  is  stopped,  the 
auxiliary  reduction  gets  ahead  of  that  in  the  brake  pipe 
at  h  so  piston  4  moves  towards  the  right  carrying  with  it 
valve  7  closing  ports  s  and  the  small  port  into  q,  this 
stops  the  flow  of  air  into  the  cylinder  and  holds  it  there. 
Another  gradual  reduction  at  the  brake  valve  produces 
the  same  effect,  till  the  pressures  are  equalized  between 
the  auxiliary  and  brake  cylinders. 

If  the  train  is  a  short  one  the  piston  and  slide  valve 
pass  by  the  quick-service  position  to  what  is  called  full 
service  position  in  which  port  o  in  valve  3  moves  past 
port  y  in  the  seat  so  no  air  passes  that  way  and.  port  3 
is  opened  full  width  to  r,  this  takes  auxiliary  air  to 
cylinder  faster  than  in  the  quick-service  position  and 
tends  to  prevent  the  triple  going  into  quick  action  on  a 
short  train.  In  quick-service  position  knob  J  on  piston 
4  touches  the  graduating  stop  21  without  compressing 
it,  in  the  full-service  position  it  compresses  the  spring  a 
little  till  its  resistance  will  stop  piston  4,  this  also  aids  in 
preventing  quick-action  applications  with  a  service  re- 
duction. It  is  the  graduated  or  "step-down"  release  that 
requires  the  most  study  to  understand.  During  a  brake 
application  the  supplementary  still  holds  the  standard 
pressure  we  had  at  the  beginning  of  the  application. 
When  the  triple  piston  4  and  the  slide  valve  3  move  to 
the  right  at  the  release,  exhaust  port  n  is  in  register  with 
r  in  the  seat,  cavity  w  in  valve  7  allows  air  from  the 
cylinder  to  pass  out  through  m  to  P.  At  the  same  time 
port  k  in  the  slide  valve  is  in  register  with  x  in  the  seat, 
so  supplementary  air  feeds  into  R  and  the  service  aux- 


124  GRADUATED    RELEASE 

iliary.  If  the  brake  pipe  pressure  in  h  has  been  raised  by 
the  brake  valve  being  left  in  full  release  so  it  is  higher 
than  the  supplementary  can  equalize  with  R,  piston  4 
will  remain  in  rull  release.  But  if  the  brake  pipe  pressure 
is  raised  a  few  pounds  and  the  brake  valve  lapped,  as  soon 
as  the  supplementary  air  coming  through  port  k  can 
raise  the  pressure  in  R  higher  than  the  brake  pipe  press- 
ure in  h,  piston  4  will  move  back  carrying  graduating 
valve  7  with  it,  closing  port  k  so  the  pressure  in  R  will 
not  rise  any  higher  and  closing  port  m  so  no  more  air 
can  pass  to  the  exhaust  from  the  cylinder,  this  allows 
part  of  the  cylinder  air  to  escape,  how  much,  depends  on 
how  long  the  exhaust  cavity  w  connects  ports  n  and  m. 
Valve  3  is  not  moved,  as  the  raise  in  pressure  in  R  is 
only  sufficient  to  move  piston  4  and  valve  7,  when  port 
k  is  closed  and  stops  the  rise  in  pressure.  Another  re- 
charge of  the  brake  pipe  and  lapping  the  brake  valve  will 
move  piston  4  and  valve  7  so  ports  k  and  m  will  be 
opened  and  more  air  will  exhaust  from  the  cylinders, 
these  recharges  at  the  brake  valve  and  exhausts  at  the 
triple  will  continue  until  all  the  air  has  escaped  from 
the  cylinder.  After  slide  valve  3  has  moved  to  release,  it 
is  a  movement  back  and  forth  of  the  graduating  valve 
that  opens  and  closes  exhaust  port  m,  supplementary 
port  k  and  brake  pipe  port  /.  The  older  makes  of  triples 
have  the  exhaust  cavity  in  slide  valve  3,  the  L  triple  has 
the  exhaust  cavity  in  graduating  valve  7.  This  explana- 
tion and  the  illustrations  will  give  a  good  idea  of  how 
to  operate  this  triple,  so  we  will  not  speak  further  of  its 
operation. 

This  type  of  triple  valve  is  being  modified  and  im- 
proved from  time  to  time  so  we  may  expect  it  to  do  still 
more  in  the  future  than  it  does  now. 

56.  Q.  How  do  you  locate  a  leak  that  lets  off  the 
brake? 

A.  If  it  leaks  off  through  piston  packing  leather  the 
air  will  blow  out  of  the  hole  in  spring  case  or  lower  head 
in  push  down  brake;  with  a  pull  up  brake,  around  piston 


TRIPLE   VALVE    DEFECTS  125 

rod  or  through  the  vent  hole  in  top  head.  A  leaky  brake 
pipe  check  valve  15  will  let  the  air  out  of  brake  cylinder 
into  the  brake  pipe,  but  only  when  brake  pipe  pressure  is 
lower  than  cylinder  pressure.  This  will  be  the  case  when 
hose  bursts  or  train  breaks  in  two,  or  engineer  reduces 
the  brake  pipe  pressure  too  much.  In  ordinary  service 
stops,  leaks  at  this  point  do  not  affect  the  work  of  the 
brake. 

A  test  for  leaky  brake  pipe  check  valve  15  in  the  quick- 
action  triples  can  be  made  at  the  brake  valve.  Reduce  the 
pressure  20  or  25  pounds  from  70,  and  if  the  air  comes 
out  full  and  strong  and  the  equalizing  piston  seats  its 
valve  promptly  without  a  leak,  make  another  reduction 
of  15  or  20  pounds  more.  With  this  reduction  the  brake 
cylinder  will  have  about  50  pounds  and  brake  pipe  30. 
If  any  brake  pipe  check  valves  leak,  the  50  pounds  will 
try  to  equalize  with  the  30,  and  make  it  more  than  the 
pressure  above  equalizing  piston,  which  will  raise  and 
let  air  blow  out  of  exhaust  as  fast  as  it  comes  past  the 
check  valve. 

To  locate  a  leaky  rotary  or  any  leak  in  brake  valve 
that  lets  off  the  brake,  set  the  brake;  close  the  cut-out 
cock  at  once;  brake  will  stay  set  and  black  hand  will 
raise  or  brake  pipe  exhaust  open.  Then  open  cut-out  cock 
and  brake  will  release  through  exhaust  port  of  triple. 

To  locate  a  leaky  graduating  valve,  set  the  brake  with 
a  light  application;  it  will  release  through  exhaust  port  of 
triple  about  as  quick  as  you  can  lap  the  brake  valve. 
Then,  after  recharging  the  auxiliary,  set  with  a  full 
application  and  brake  should  stay  set. 

When  a  leaky  graduating  valve  lets  off  the  brake  with 
a  light  application,  it  is  because  the  air  from  the  auxiliary 
leaks  past  the  seat  of  valve  7  into  the  brake  cylinder 
until  the  auxiliary  pressure  is  enough  lower  than  brake 
pipe  pressure  so  triple  piston  will  move  slide  valve  up 
into  exhaust  position,  releasing  air  from  brake  cylinder 
through  the  exhaust  port.  This  it  cannot  do  with  a  full 
application,  as  in  this  case  the  air  pressure  has  equalized 


126  BRAKE    DEFECTS 

Between  the  auxiliary  and  cylinder,  so  a  leaky  valve  cuts 
no  figure;  air  will  not  pass  through  after  pressures  are 
equal.  A  leaky  piston  ring  in  the  triple  makes  this  matter 
worse,  as  the  brake  pipe  and  cylinder  pressures  can 
equalize  and  stick  the  brake.  A  leaky  triple  usually  is  in 
bad  order  in  other  ways. 

57.  Q.     If  the  brake  is  defective  and  leaks  off  through 
piston  packing,  or   any  leaks   in  piping  to  brake  cylinder, 
is  it  any  advantage  to  let  all  the  air  out  of  brake  pipe  in 
such  a  case? 

A.  It  seems  to  make  a  leaking  brake  hold  a  little 
longer,  but  it  is  so  short  a  time  that  it  does  not  help  very 
much  to  stop  the  train.  A  gage  put  on  this  brake  cylinder 
will  show  that  it  only  holds  for  a  few  seconds,  and  during 
that  time  with  a  light  pressure.  The  proper  way  is  to  stop 
the  leak. 

58.  Q.     What  makes  the  driver  brake  so  slow  to  take 
hold  if  coupled  to  a  train  when  it  works  all  right  if  engine 
and  tender  are  working  without  a  train? 

A.  Generally  it  is  because  it  leaks  somewhere,  so  the 
air  leaks  out  without  setting  the  brake  when  a  light  reduc- 
tion is  made  for  the  train  brake.  See  about  the  leaks  the 
first  thing.  The  piston  packing  leather  gets  dry  and  hard 
from  being  so  close  to  the  fire  box  and  it  needs  soaking 
up  with  oil  frequently  in  the  summer  time.  Tallow  and 
oil  is  good  to  put  in  driver  brake  cylinders,  as  it  does 
not  evaporate  so  quickly  as  oil  and  keeps  the  packing 
leather  soft  and  pliable.  To  test  for  leaks,  set  the  four- 
way  cock  in  plain  triple  for  straight  air  (if  possible)  ; 
or  set  the  straight  air;  this  will  give  you  time  to  go 
around  and  find  the  leaks.  If  the  piston  leather  leaks, 
the  air  will  blow  out  of  hole  in  the  spring  case  or  lower 
head  of  push-down  brake.  Using  the  brake  valve  on 
direct  application  position  for  service  stops  will  sometimes 
kick  the  driver  brake  off,  after  setting  the  train  brake. 
This  is  because  when  you  use  the  direct  application  port 
to  set  the  brake  you  make  a  heavier  reduction  at  head 
end  of  the  brake  pipe  than  at  rear  end.  The  head  end 


BRAKE     DEFECTS  127 

triples  equalize  for  this  reduction ;  air  from  rear  end 
rushes  up  after  you  close  the  brake  valve  and  releases 
head  triples.  This  is  another  reason  why  the  direct 
application  should  never  be  used  unless  you  want  the 
emergency  action  of  every  brake. 

59.  Q.     Why    does    the    tender    brake    sometimes    stick 
and  refuse  to  let  off  till  auxiliary   is  bled  a  little,  when 
all  the  other  brakes  on  the  train  release  promptly? 

A.  Generally  because  not  enough  excess  pressure  is 
carried.  Always  carry  a  sufficient  excess  if  you  want  the 
automatic  brake  to  work  properly.  Overcharging  the 
head  end  of  a  long  train  will  usually  make  the  head  brakes 
apply  and  if  the.  brake  pipe  pressure  drops  a  little  they 
will  stick  till  kicked  off  by  going  to  full  release  for  a 
few  seconds.  Some  old  tenders  have  12  x  33-inch  aux- 
iliary reservoirs  for  an  8-inch  brake  cylinder;  if,  in  this 
case,  the  piston  travel  is  short,  the  brake  piston  pressure 
is  six  or  seven  pounds  higher  than  other  brakes  equalize 
at  and  brake  pipe  pressure  must  be  raised  correspond- 
ingly higher  to  release  tender  brake.  Then  the  tender 
triple  gets  more  sand  and  dirt  in  it  than  any  other  triple, 
which  causes  it  to  wear  and  get  defective.  A  leaky  triple 
piston  packing  ring  will  allow  any  brake  to  stick  unless 
very  high  excess  is  used,  as  it  will  let  air  equalize  past 
the  triple  piston  into  auxiliary  without  moving  piston  up 
to  exhaust  position. 

60.  Q.     If  the   brake  pipe   is   charged  up  with   a   high 
pressure  from  main  reservoir  when  brake  is  released  for 
a  second  application  stop,  will  the  brake  set  again  at  once 
with  a  small  reduction  of  brake  pipe  pressure? 

A.  It  will  not  set  again  until  the  brake  pipe  pressure 
is  reduced  below  the  auxiliary  pressure.  For  example : 
If  the  brake  has  been  set  tight,  the  auxiliary  pressure 
will  be  about  50  pounds  for  the  first  application;  if  you 
turn  90  pounds  into  brake  pipe  you  must  let  40  pounds 
out  again,  to  draw  brake  pipe  pressure  below  50,  before 
the  triple  piston  will  move;  all  this  time  your  train  is 
getting  nearer  the  stopping  point.  This  is  one  of  the. 


128  STICKING  BRAKES 

reasons  why  you  run  by  when  trying  to  make  a  stop  this 
way;  it  takes  so  long  to  draw  your  brake  pipe  pressure 
down  where  it  was  before.  In  case  you  expect  to  apply 
the  brake  at  once  after  releasing  it  wholly  or  partly,  put 
the  brake  valve  on  full  release  for  an  instant,  just  long 
enough  to  charge  up  the  brake  pipe  its  whole  length,  and 
then  put  it  on  lap.  This  movement  will  release  triples 
and  hold  your  brake  pipe  pressure  so  near  the  auxiliary 
pressure  that  the  triple  is  ready  to  act  instantly  with  light 
service  application.  This  is  the  proper  method  of  making 
partial  release  if  you  are  going  to  stop  too  soon  or  expect 
that  slippery  track  will  skid  the  wheels  just  as  the  final 
stop  is  made. 

61.  Q.     Why  are  some  of  the  train  brakes  more  likely 
to  stick  on  a  long  train  after  a  light  application  than  after 
a  heavier  one? 

A.  Because  after  a  light  application  the  pressure  has 
been  reduced  so  little  in  the  auxiliaries  that  the  main 
reservoir  does  not  have  enough  more  pressure  to  move  all 
the  triples.  A  light  reduction  on  a  long  train  does  not 
always  move  all  the  triple  pistons  and  their  feed  ports 
remain  open  ready  to  take  brake  pipe  air,  which  holds  the 
brake  pipe  pressure  down.  With  a  heavy  reduction  the 
triples  all  operate,  no  feed  ports  will  be  open  till  triples 
release  and  the  brake  pipe  pressure  will  raise  higher  at  the 
moment  of  releasing  brakes.  This  is  a  trouble  peculiar 
to  long  trains  only;  small  main  reservoirs  and  sticky 
triples  with  leaky  packing  rings  make  it  worse. 

62.  Q.     Is  it  possible  to  let  off  part  of  the  brakes  and 
leave  part  of  them   set? 

A.  Yes.  After  a  full  application  this  can  be  done, 
especially  if  brake  pipe  pressure  has  been  reduced  much 
more  than  20  pounds.  When  you  go  to  full  release,  if 
the  brake  pipe  is  not  at  once  charged  up  above  the  highest 
auxiliary  pressures  by  the  main  reservoir  air,  as  soon  as 
the  brake  pipe  pressure  is  a  little  higher  than  the  lowest 
pressure  in  any  auxiliary,  its  triple  will  move  up  into 
exhaust  position,  releasing  that  brake.  Then  this  auxiliary 


BRAKES    CREEPING    ON  129 

will  begin  to  recharge  through  feed  port  and  help  hold 
brake  pipe  pressure  down  till  that  auxiliary  and  the  brake 
pipe  are  charged  up  high  enough,  when  another  brake 
will  let  off;  and  so  on  until  all  are  let  off.  The  brake 
with  longest  piston  travel  usually  lets  off  first,  because  it 
has  the  lowest  auxiliary  pressure;  this  operation  takes 
place  after  a  full  application  when  piston  travels  are 
unequal.  When  pumping  off  the  stuck  brakes  you  have 
to  raise  the  pressure  in  all  the  auxiliaries  of  the  released 
brakes  as  well  as  in  the  brake  pipe.  When  you  think  the 
brakes  are  releasing  in  this  manner,  lap  the  brake  valve 
and  pump  up  the  excess ;  when  this  is  turned  back  into 
the  brake  pipe  they  will  usually  all  let  go.  Do  not  attempt 
to  work  steam,  you  will  risk  a  break-in-two. 

63.  Q.     Why   do    some   of   the   brakes    creep   on   when 
the  train  is  running? 

A.  Because  there  is  a  leak  that  takes  air  out  of  the 
brake  pipe;  this  leak  may  be  in  the  brake  pipe,  triple  valve 
or  auxiliary  reservoirs.  It  can  also  be  on  account  of  the 
auxiliaries  not  having  all  equalized  after  releasing  the 
brake.  The  auxiliaries  at  the  head  end  of  train  will  charge 
to  a  higher  pressure  on  full  release  than  the  rear  ones; 
when  the  brake  valve  is  moved  to  running  position  the 
higher  auxiliary  pressure  will  cause  the  head  triples  to 
move  to  service  position.  If  air  is  fed  into  the  brake  pipe 
faster  than  it  leaks  out,  the  brakes  will  not  creep  on.  If 
air  sanders  use  so  much  air  that  the  pump  can  not  supply 
air  to  hold  up  main  reservoir  and  brake  pipe  pressures 
the  brake  will  set;  this  is  a  main  reservoir  leak  taking 
air  out  of  brake  pipe. 

64.  Q.    How  can  these  brakes  be  released  the  quickest 
and  surest  way? 

A.  If  a  main  reservoir  leak  reduces  brake  pipe  press- 
ure, shut  off  the  escape  of  air  if  possible  and  run  the 
pump  faster  till  brake  pipe  pressure  is  raised  so  brakes 
will  release.  If  a  leak  from  brake  pipe  sets  the  brake,  see 
that  you  have  excess  pressure  first,  then  turn  it  back  into 
brake  pipe  by  moving  the  brake  valve  handle  from  run- 


130  STICKING   BRAKES 

ning  position  to  full  release  just  long  enough  so  the  rush 
of  air  from  main  reservoir  will  charge  up  the  brake  pipe, 
and  putting  it  back  to  running  position  before  any  of  the 
auxiliaries  are  charged  any  higher.  This  forces  the  triple 
valves  of  the  sticking  brakes  up  into  release  position,  so 
air  from  brake  cylinder  exhausts  and  does  not  give  time 
to  raise  the  pressure  in  any  reservoir.  Sometimes  this 
must  be  done  a  second  and  third  time  to  release  all  of 
them.  If  brake  valve  is  held  on  full  release  long  enough 
to  charge  a  reservoir  higher  than  the  standard  brake  pipe 
pressure,  that  brake  will  be  sure  to  set  as  soon  as  brake 
valve  is  returned  to  running  position.  This  is  the  case 
when  the  feed  ports  are  too  large  in  proportion  to  the 
auxiliaries  that  they  supply. 

65.  Q.     If    governor    is    set    at    70    pounds    with    D-8 
valve  or  any  brake  valve  of  that  type,  and  brake  pipe  is 
charged   from   main  reservoir   higher  than  that  pressure, 
is  the  brake  apt  to  creep  on? 

A.  Yes;  the  pump  is  stopped  and  will  not  start  again 
till  brake  pipe  pressure  is  lowered  to  70  pounds.  The 
excess  valve  will  remain  shut  so  no  air  can  pass  into  the 
brake  pipe,  and  if  there  are  any  leaks  the  train  pipe  press- 
ure will  drop.  During  this  time  brake  is  pretty  sure  to 
go  on. 

66.  Q.    How  can  this  be  avoided? 

A.  By  not  allowing  main  reservoir  to  charge  brake 
pipe  and  auxiliaries  at  over  70  pounds.  When  standing 
at  a  water  tank,  or  any  stop,  with  brakes  set,  the  main 
reservoir  pressure  is  apt  to  run  very  high.  If  all  of  this 
is  turned  into  brake  pipe  and  allowed  to  equalize  at  over 
70  pounds,  with  brake  valve  carried  in  full  release  reg- 
ularly, there  is  no  way  to  prevent  the  brake  setting  if 
brake  pipe  leaks.  In  this  case,  set  it  a  little  and  at  once 
release  it;  this  will  reduce  the  brake  pipe  and  auxiliaries 
below  70  pounds,  so  pump  will  go  to  work  and  you  can 
hold  brake  off. 

67.  Q.     In  making  a  stop  how  should  you  release  the 
brakes  on  a  freight  train?     On  a  passenger  train? 


RELEASING    BRAKES  131 

A.  On  a  freight  train,  not  till  it  has  entirely  stopped, 
or  you  run  the  risk  of  train  breaking  in  two.  The  brake 
pipe  pressure  on  a  long  train  is  increased  next  the  engine 
first;  hence  brakes  let  go  there  first;  even  if  it  is  only  a 
few  seconds  sooner.  Part  of  the  shock  is  from  unequal 
piston  travel,  which  gives  unequal  piston  pressure ;  brakes 
with  long  piston  travel  let  go  first  after  a  full  application. 
With  a  "part  air"  train  the  slack  of  entire  train  runs  up 
'  against  the  head  cars ;  releasing  brake  while  train  is 
moving  slowly,  is  liable  to  part  the  train;  working  steam 
before  slack  is  all  evened  up  in  train  is  sure  to  break  it  in 
two.  The  ET  brake  and  K  triples  will  hold  the  slack 
against  the  engine.  Using  pressure  retainers  on  the  head 
end  of  such  a  train  or  the  Straight  Air  brake  on  engine 
will  hold  the  slack  all  bunched  till  all  triples  have  released 
when  retainer  handle  can  be  turned  down  or  engine  brake 
released. 

With  a  passenger  train,  release  should  be  made  just  a 
few  feet  before  the  train  stops,  so  there  will  be  just 
enough  power  to  stop  the  train  and  avoid  tilting  the 
coach  truck  forward  at  the  instant  the  train  stops.  If 
the  brake  beams  are  hung  from  the  body  of  the  car  the 
truck  will  not  tilt  forward,  but  there  will  be  a  shock  at 
stopping  if  the  brake  power  is  severe. 

68.  Q.  Why  should  a  brake  on  a  short  passenger  train 
be  let  off  just  before  coming  to  a  full  stop? 

A.  Because,  as  most  all  coaches  have  outside  hung 
brakes,  the  brake  shoes  pull  down  on  the  forward  end  of 
the  truck  and  push  up  on  the  back  part  of  the  truck  and 
thus  tilt  the  truck;  if  brake  is  not  let  off  until  after  the 
train  stops,  when  the  truck  rights  itself  it  rolls  the  wheels 
back  a  little  and  throws  the  body  of  the  coach  back, 
annoying  the  passengers,  even  if  it  is  not  severe  enough 
to  throw  them  against  the  seats.  This  trouble  is  not  felt 
so  plainly  by  the  engineer  when  he  has  a  good  driver  and 
tender  brake,  as  the  brake  on  the  coach  is  what  jerks  the 
coach.  Then  less  power  is  required  to  stop  a  train  going 
very  slow,  as  at  the  instant  of  stopping,  than  when  run- 


134  INSPECTING    BRAKES 

style    of    angle    cock    handle    prevents    the    plug    turning 
around. 

74.  Q.     1.     After    coupling    to    train    why    should    you 
not   immediately  try  to   apply  the  brakes   for   inspection? 
2.     How   long  should  you   wait? 

A.  Because  you  must  wait  till  a  full  pressure  of  70 
pounds  is  stored  in  auxiliaries  so  a  full  application  of 
brakes  can  be  obtained  to  get  the  piston  travel.  The  time 
you  should  wait  depends  on  the  pressure  maintained  in 
the  brake  pipe  from  the  moment  of  coupling  on;  if  70 
pounds  is  held  steadily,  two  and  one-half  minutes  is  the 
shortest  time  for  some  of  the  older  makes  of  triples.  The 
triple  valves  of  late  design  charge  to  70  pounds  in  about 
seventy  seconds.  The  pressures  must  be  equal  in  all 
the  auxiliaries,  even  if  it  takes  longer  before  testing. 
When  the  governor  stops  the  pump  with  the  standard 
pressures  shown  on  both  hands  of  the  gage  it  is  usually 
long  enough.  j  •*  j 

75.  Q.     Should  the  train  brakes  be  inspected?     How? 
When?     Why? 

A.  Yes,  by  applying  them  with  full  service  application 
in  the  same  manner  as  for  a  station  stop  with  a  moving- 
train;  then  examine  each  car  to  see  that  the  piston  travel 
is  the  proper  length  and  that  there  are  no  leaks  that  will 
let  brakes  off;  then  release  them  and  examine  each  car  to 
see  that  all  release  and  that  there  are  no  leaks  through 
exhaust  port.  They  should  be  inspected  at  all  terminals 
and  tested  whenever  train  breaks  in  two,  or  cars  are  taken 
on  or  set  off,  as  the  wrong  angle  cocks  may  be  closed  or 
left  closed  at  such  points.  This  is  necessary  because  it  is 
not  safe  to  depend  on  a  brake  till  it  is  shown  that  it  will 
set  and  release  properly.  Hand  brake  should  always  be 
let  off  before  testing.  If  pressure  retaining  valves  are 
tested  they  should  be  turned  up  after  the  first  test  is  com- 
pleted, a  reduction  of  ten  pounds  made  in  brake  pipe,  and 
the  brake  pipe  recharged  to  release  the  triples.  The  re- 
tainers should  then  be  examined  to  see  that  they  are  all 
quiet;  handles  should  then  be  turned  down.  If  they  are 


INSPECTING     BRAKES  135 

in  good  order  the  air  held  in  brake  cylinder  will  come  out 
as  soon  as  handle  is  turned  down.  If  no  air  blows  out  the 
retainer  is  useless,  look  for  leaks  at  pipe  joints  and  brake 
cylinder  packing. 

76.  Q.     Would  you  consider  a  train  safe  to  leave  with 
if  the  brakes   had  been   tested  by  opening  angle   cock   at 
rear  of  train?    How  would  this  affect  your  main  reservoir 
pressure  ? 

A.  No,  sir !  not  unless  some  other  test  has  been  made. 
This  would  not  set  all  the  brakes  unless  the  brake  valve 
was  on  lap.  It  would  draw  down  main  reservoir  pressure 
and  waste  air  without  doing  any  good.  This  test  is  only 
good  to  show  that  air  hose  are  coupled,  angle  cocks  open 
and  brake  pipe  charged  from  engine  to  last  car. 

77.  Q.     If    with    70    pounds    brake    pipe    and    auxiliary 
pressure  you  release  the  brake  and  apply  it  "again  imme- 
diately, would  you   expect  to  obtain  the   same  power  you 
had    before?      How    long    would    it    take    to    regain    the 
original  pressure? 

A.  No,  sir !  never.  About  forty  seconds,  if  main 
reservoir  had  35  or  40  pounds  excess  over  auxiliaries, 
sometimes  less  time.  The  feed  ports  in  triple  valves 
which  regulate  the  time  of  charging  are  not  always  the 
proper  size  for  the  reservoirs  they  supply.  A  short  train 
and  light  application  would  reduce  this  time  to  twenty 
or  twenty-five  seconds.  Generally  it  takes  longer  than 
the  tests  show  it  with  everything  in  good  working  order, 
for  the  feed  ports  are  not  always  clean  and  strainers  free. 
The  pressure  at  which  auxiliary  equalized  after  first  ap- 
plication is  what  you  begin  with  on  second  application 
after  first  release,  generally  it  is  fifty  after  first  full 
application ;  with  full  release  of  brake  and  immediate 
application  you  get  thirty-five  and  a  little  more  on  second 
full  application ;  the  third  time  you  will  have  less  than 
30  pounds  piston  pressure. 

With  the  High  Speed  brake  pressure  of  110  pounds 
you  can  make  two  successive  applications  with  20  pound 
reductions  and  a  release  between  before  you  get  down 


134  INSPECTING    BRAKES 

style    of    angle    cock    handle    prevents    the    plug    turning 
around. 

74.  Q.     1.     After    coupling    to    train    why    should    you 
not   immediately  try  to   apply  the  brakes   for   inspection? 
2.     How   long,  should  you   wait? 

A.  Because  you  must  wait  till  a  full  pressure  of  70 
pounds  is  stored  in  auxiliaries  so  a  full  application  of 
brakes  can  be  obtained  to  get  the  piston  travel.  The  time 
you  should  wait  depends  on  the  pressure  maintained  in 
the  brake  pipe  from  the  moment  of  coupling  on;  if  70 
pounds  is  held  steadily,  two  and  one-half  minutes  is  the 
shortest  time  for  some  of  the  older  makes  of  triples.  The 
triple  valves  of  late  design  charge  to  70  pounds  in  about 
seventy  seconds.  The  pressures  must  be  equal  in  all 
the  auxiliaries,  even  if  it  takes  longer  before  testing. 
When  the  governor  stops  the  pump  with  the  standard 
pressures  shown  on  both  hands  of  the  gage  it  is  usually 
long  enough.  >;  !.• 

75.  Q.     Should   the   train  brakes   be  inspected?     How? 
When?     Why? 

A.  Yes,  by  applying  them  with  full  service  application 
in  the  same  manner  as  for  a  station  stop  with  a  moving- 
train;  then  examine  each  car  to  see  that  the  piston  travel 
is  the  proper  length  and  that  there  are  no  leaks  that  will 
let  brakes  off;  then  release  them  and  examine  each  car  to 
see  that  all  release  and  that  there  are  no  leaks  through 
exhaust  port.  They  should  be  inspected  at  all  terminals 
and  tested  whenever  train  breaks  in  two,  or  cars  are  taken 
on  or  set  off,  as  the  wrong  angle  cocks  may  be  closed  or 
left  closed  at  such  points.  This  is  necessary  because  it  is 
not  safe  to  depend  on  a  brake  till  it  is  shown  that  it  will 
set  and  release  properly.  Hand  brake  should  always  be 
let  off  before  testing.  If  pressure  retaining  valves  are 
tested  they  should  be  turned  up  after  the  first  test  is  com- 
pleted, a  reduction  of  ten  pounds  made  in  brake  pipe,  and 
the  brake  pipe  recharged  to  release  the  triples.  The  re- 
tainers should  then  be  examined  to  see  that  they  are  all 
quiet;  handles  should  then  be  turned  down.  If  they  are 


INSPECTING     BRAKES  135 

in  good  order  the  air  held  in  brake  cylinder  will  come  out 
as  soon  as  handle  is  turned  down.  If  no  air  blows  out  the 
retainer  is  useless,  look  for  leaks  at  pipe  joints  and  brake 
cylinder  packing. 

76.  Q.     Would  you  consider  a  train  safe  to  leave  with 
if  the   brakes   had   been   tested   by   opening   angle   cock  •; at 
rear  of  train?    How  would  this  affect  your  main  reservoir 
pressure? 

A.  No,  sir !  not  unless  some  other  test  has  been  made. 
This  would  not  set  all  the  brakes  unless  the  brake  valve 
was  on  lap.  It  would  draw  down  main  reservoir  pressure 
and  waste  air  without  doing  any  good.  This  test  is  only 
good  to  show  that  air  hose  are  coupled,  angle  cocks  open 
and  brake  pipe  charged  from  engine  to  last  car. 

77.  Q.     If    with    70    pounds    brake    pipe    and    auxiliary 
pressure  you  release  the  brake  and  apply  it  "again  imme- 
diately, would  you   expect  to  obtain  the   same  power  you 
had    before?      How    long    would    it    take    to    regain    the 
original  pressure? 

A.  No,  sir !  never.  About  forty  seconds,  if  main 
reservoir  had  35  or  40  pounds  excess  over  auxiliaries, 
sometimes  less  time.  The  feed  ports  in  triple  valves 
which  regulate  the  time  of  charging  are  not  always  the 
proper  size  for  the  reservoirs  they  supply.  A  short  train 
and  light  application  would  reduce  this  time  to  twenty 
or  twenty-five  seconds.  Generally  it  takes  longer  than 
the  tests  show  it  with  everything  in  good  working  order, 
for  the  feed  ports  are  not  always  clean  and  strainers  free. 
The  pressure  at  which  auxiliary  equalized  after  first  ap- 
plication is  wrhat  you  begin  with  on  second  application 
after  first  release,  generally  it  is  fifty  after  first  full 
application ;  with  full  release  of  brake  and  immediate 
application  you  get  thirty-five  and  a  little  more  on  second 
full  application ;  the  third  time  you  will  have  less  than 
30  pounds  piston  pressure. 

With  the  High  Speed  brake  pressure  of  110  pounds 
you  can  make  two  successive  applications  with  20  pound 
reductions  and  a  release  between  before  you  get  down 


136  SIZE    OF    FEED    PORT 

to   70   pounds   with   the   type   L   triple,   the   supplementary 
reservoir  recharges  the  service  auxiliary  almost  instantly. 

78.  Q.     Can  an  auxiliary  reservoir  be  recharged   with- 
out releasing  the  brake? 

A.  No,  not  if  the  triple  valve  is  in  good  order.  The 
ports  are  so  located  in  the  triple  valve  that  the  feed  port 
through  which  auxiliary  is  charged  does  not  open  till  after 
exhaust  port  is  open,  which  releases  the  brake  first, 
recharge  the  auxiliary  afterward.  By  the  use  of  a  press- 
ure retaining  valve,  which  holds  some  of  the  air  in  the 
brake  cylinder,  the  auxiliary  can  be  recharged  without 
releasing  the  brake  entirely.  If  an  auxiliary  is  recharged 
before  the  triple  is  moved  to  exhaust  position,  brake  pipe 
pressure  will  not  be  able  to  move  the  triple,  and  the 
brake  must  be  bled  off. 

79.  Q.     Why  does  it  take  so  long  to  regain  the  original 
pressure  in  the  auxiliaries  after  releasing  brakes? 

A  because  the  feed  port  in  the  triple  through  which 
the  air  passes  from  brake  pipe  to  auxiliary  is  small.  This 
feed  port  is  shown  at  m  in  the  plain  triple,  and  at  i  in 
the  quick-action  triple.  It  is  necessary  to  have  this  port 
small  for  two  reasons;  first — when  setting  the  brake,  the 
feed  port  must  be  small  or  when  brake  pipe  pressure  is 
reduced  at  brake  valve  for  a  light  service  application,  the 
auxiliary  air  could  flow  around  the  triple  piston  through 
the  feed  port  i  as  fast  as  it  is  taken  out  of  brake  pipe; 
so  triple  piston  would  not  move.  If  the  feed  ports  were 
larger,  when  brakes  are  to  be  released,  it  would  be  im- 
possible to  charge  up  a  long  brake  pipe  from  the  engine 
and  hold  the  pressure  up  quick  enough  to  release  all  the 
brakes  at  as  nearly  the  same  instant  as  possible,  as  the 
first  few  ports  to  open  would  take  some  of  the  brake  pipe 
air  and  hold  the  pressure  down;  if  they  were  large 
enough  a  few  of  them  would  do  this.  The  quick-service 
triples  and  L  triples  are  now  arranged  to  help  this  matter 
out.  See  questions  46  and  55.  These  feed  ports  must 
be  the  proper  size  for  the  auxiliaries  they  supply,  so 
different  sized  auxiliaries  will  charge  to  the  same  pressure 


LEAKAGE    GROOVE  137 

in  the  same  time  from  the  same  brake  pipe.  The  auxiliary 
reservoir  for  a  10-inch  coach  brake  holds  about  3,100 
cubic  inches,  that  for  an  8-inch  freight  brake  holds  about 
1,620  inches;  therefore  a  feed  port  for  a  10-inch  brake 
reservoir  must  be  the  right  size  to  pass  nearly  twice  as 
much  air  through  in  the  same  given  time  as  for  an  8-inch 
brake.  This  is  the  reason  for  using  only  the  proper  triple 
for  each  reservoir.  Then  the  reservoirs  are  a  certain  size 
for  the  brake  cylinders  they  supply,  so  an  auxiliary  press- 
ure of  70  pounds  will  equalize  with  brake  cylinder  of  8 
inches  piston  travel  at  50  pounds.  This  in  turn  gives  a 
standard  piston  pressure  for  which  to  arrange, the  brake 
leverage  on  each  car  or  engine,  so  as  to  get  the  full 
effective  braking  power.  The  older  style  of  plain  triples, 
F-24,  used  with  8-inch  engine  brakes,  have  feed  ports 
the  proper  size  for  12  x  33  auxiliaries.  This  gives  a 
quicker  recharging  and  a  prompter  application  with  these 
brakes  in  switching  service.  If  engine  brake  creeps  on 
from  this  cause  when  coupled  to  a  train  they  are  easily 
released  from  the  brake  valve  as  they  are  close  to  the 
brake  valve  and  main  reservoir.  The  present  style  of 
plain  triples,  G-24,  have  the  proper  sized  feed  ports  for 
the  8-inch  brake. 

80.  Q.  Where  are  leakage  grooves  located?  What 
are  they  for?  Is  it  necessary  to  allow  for  them  when 
applying  the  brake?  How  do  you  do  this? 

A.  Leakage  grooves  are  small  grooves  cut  in  the 
inside  of  brake  cylinders  at  the  top  or  side.  The  later 
freight  brake  cylinders  have  them  at  the  side.  When  the 
brake  piston  is  in  release  position  this  groove  is  uncovered 
so  that  a  small  amount  of  air  passing  into  the  brake 
cylinder  from  a  very  light  application,  or  when  the  brakes 
are  creeping  on,  will  escape  through  the  groove  without 
moving  the  piston.  When  the  triple  valve  is  in  release 
position  any  air  that  gets  into  the  cylinder  from  leaks  can 
pass  out  through  the  exhaust.  They  also  prevent  the 
brake  holding  when  the  piston  travel  is  taken  up  too 
short.  In  old  equipment  they  are  long  enough  so  that  a 


138  PISTON    TRAVEL 

piston  movement  of  three  inches  is  necessary  to  cover  the 
groove,  in  later  equipment  they  are  much  shorter.  It  is 
necessary  to  allow  for  them  at  the  first  reduction  by  mak- 
ing it  strong  enough  so  that  the  brake  piston  will  go  far 
enough  at  the  first  movement  to  cover  the  groove.  Five 
to  seven  pounds  reduction  should  do  this ;  a  short  train 
does  not  take  as  heavy  a  reduction  as  a  long  one.  The 
leakage  groove  must  be  covered  at  the  first  reduction  or 
the  air  passing  into  the  cylinder  will  be  wasted,  a  number 
of  small  reductions  will  waste  all  the  air  so  train  cannot 
be  stopped.  This  is  a  common  fault  in  operating  the 
brake.  If  the  hand  brake  is  set  on  a  coach  or  the  piston 
travel  shortened  so  the  leakage  groove  is  not  covered, 
that  brake  will  not  hold. 

81.  Q.  Does  the  difference  in  travel  of  pistons  in 
brake  cylinders  increase  or  decrease  your  braking  power? 
Why? 

A.  Long  piston  travel  decreases  the  braking  power 
because  it  gives  less  air  pressure  on  piston,  short  piston 
travel  gives  higher  piston  pressure.  With  light  applica- 
tions this  difference  is  more  marked  than  with  a  full 
application.  A  10  pound  reduction  will  apply  a  4-inch 
travel  brake  solid,  while  it  will  not  give  any  braking 
power  with  an  11-inch  travel.  With  8-inch  piston  travel, 
70  pounds  auxiliary  pressure  gives  50  pounds  on  piston 
per  square  inch.  An  inch  difference  in  the  travel  make 
close  to  two  pounds  in  pressure,  thus  7  inches  would  give 
nearly  52  pounds,  9  inches  a  little  over  48  pounds.  The 
piston  travel  can  be  correct  with  a  heavy  car  and  high 
leverage,  and  the  shoes  will  not  clear  the  wheel  much 
when  released.  If  levers  and  brake  beams  spring  much 
with  8-inch  travel,  the  shoes  will  not  have  much  slack 
when  let  off.  Brake  levers  may  catch  on  something  so 
piston  travel  is  correct  and  shoes  not  touch  the  wheels. 
With  the  straight  air  brake  or  the  distributing  valve  the 
piston  travel  does  not  affect  the  pressure  on  the  brake 
piston,  as  these  valves  do  not  take  air  from  an  auxiliary 
as  the  triple  valve  does. 


CUTTING    OUT    BRAKES  139 

82.  Q.     How  do  you  cut  out  the  brake  on  engine  and 
tender  without  interfering  with  the  train  brake? 

A.  By  turning  the  four-way  cock  in  top  of  old  style 
plain  triple  so  the  handle  is  at  an  angle  of  forty-five 
degrees ;  this  will  lap  all  ports  and  allow  no  air  to  pass 
from  brake  pipe  or  auxiliary  to  brake  cylinder;  see  that 
brake  is  entirely  released  first,  and  open  bleeder  in  aux- 
iliary. With  the  later  type  of  engine  triple  the  cut-out 
cock  is  in  the  cross-over  pipe,  so  closing  the  cock  cuts 
out  the  triple.  Open  bleeder  in  auxiliary  so  the  brake 
cannot  creep  on  from  a  leak  in  the  triple.  To  cut  out  the 
locomotive  brake  from  the  distributing  valve,  shut  the 
cock  in  the  pipe  leading  to  the  cylinders.  To  cut  out 
the  automatic  action  of  the  distributing  valve  close  the 
cock  in  the  brake  pipe  connection. 

83.  Q.    What,  is  the  difference  between  cutting  the  air 
out  from  a  car  and  cutting  it  out  from  a  brake? 

A.  Shutting  the  angle  cock  at  the  end  next  engine 
cuts  out  that  car  and  all  behind  it;  shutting  the  cross- 
over cock  between  brake  pipe  and  triple  cuts  out  that 
brake  only  and  allows  all  the  rest  to  operate. 

84.  Q.     If   one   brake   beam    under    a    car    was    broken 
how  would  it  affect  that  brake?     How  would  you  cut  out 
the  brake  on  that  car  and  allow  air  to  pass  to  other  cars? 

A.  If  one  brake  beam  or  rod  is  broken,  the  brake  on 
that  car  is  useless  and  it  must  be  cut  out  by  shutting  the 
cock  in  the  cross-over  from  brake  pipe  to  triple,  or  by 
turning  the  four-way  cock  in  plain  triple.  This  will  allow 
air  to  pass  through  brake  pipe  to  other  cars  without 
operating  disabled  brake.  Be  sure  the  brake  with  plain 
triple  on  either  engine,  tender  or  coach  is  released  before 
four-way  cock  is  turned,  as  no  air  can  get  out  of  brake 
cylinder  after  cock  is  turned.  All  quick-action  brakes  can 
be  bled  by  opening  the  bleeder  in  auxiliary  reservoir  and 
allowing  all  air  to  escape,  as  the  cut-out  cock  does  not 
close  the  communication  between  brake  cylinder  and  the 
bleed  cock  in  auxiliary. 

85.  Q.     In  going  down  a  long,  steep  grade  how  would 


140  HANDLING    TRAINS    ON    GRADES 

you   handle   the  brake  to  control   the  train?     Why  is   it 
necessary  to  recharge  the  auxiliaries  on  a  hill?     How  is  " 
this  done? 

A.  Air  braked  trains  on  a  long,  steep  grade  must  be 
taken  down  at  a  moderate  speed  in  order  to  control  the 
train;  much  less  brake  power  will  hold  it  at  a  slow  speed 
than  a  fast  one.  If  the  train  once  gets  the  start  of  you  it 
may  not  be  held  at  all.  Run  slow  enough  so  you  will  not 
need  all  the  brake  power  to  steady  the  train  or  you  will 
not  be  able  to  stop  when  necessary.  When  first  passing 
the  top  of  a  long,  steep  down  grade,  set  the  brake  and 
see  if  you  can  stop;  if  satisfied,  release  and  go  on,  if  not 
satisfied  the  brakes  will  hold  train,  call  for  help  and  get 
stopped. 

Leaks  in  brake  pipe,  auxiliary,  or  brake  cylinder  press- 
ures make  it  necessary  to  recharge;  very  few  if  any  trains 
are  absolutely  air  tight.  If  brake  pipe  leaks,  the  brake 
will  set  at  full  power,  which  should  stop  the  train;  this 
will  call  for  a  release  and  recharging  to  standard  pressure. 
Auxiliary  or  brake  cylinder  leaks  will  reduce  the  braking 
power  so  train  will  run  away;  to  avoid  this  disaster  it  is 
necessary  to  recharge  the  auxiliaries  frequently;  you  can 
then  hold  the  auxiliary  pressure  up  close  to  the  standard 
amount  all  the  way  down  the  hill  and  have  plenty  of 
brake  power.  As  triple  valves  release  a  brake  and  re- 
charge the  auxiliary  afterward,  to  hold  the  brake  set  while 
auxiliaries  are  recharging,  pressure  retaining  valves  are 
used,  which  hold  some  of  the  air  in  the  cylinder  after 
triple  has  gone  to  release  position.  Before  starting  down 
the  grade  turn  up  the  handles  or  retainers,  use  as  many 
as  possible  and  not  have  them  stop  the  train  at  any  of  the 
let-ups  in  the  grade.  The  more  retainers  used  the  less 
hot  wheels,  as  the  holding  power  is  on  a  greater  number 
of  cars ;  if  the  full  brake  power  is  used  on  any  cars  all  the 
way  down  a  long  hill  the  wheels  are  liable  to  get  so  hot 
as  to  damage  them.  Make  a  moderate  application  at  first; 
when  the  train  slows  down,  release  and  leave  brake  valve 
in  full  release  position  to  recharge  as  quickly  as  possible, 


HANDLING    A   TRAIN  141 

which  should  not  take  over  forty-five  seconds.  On  the 
next  application,  a  light  reduction  will  usually  steady  the 
train,  as  with  retainers  used  the  pistons  are  over  the 
leakage  grooves  and  considerable  pressure  held  in  the 
cylinders.  Light  reductions  give  more  power  to  brakes 
with  retainers  working  than  heavy  reductions  without 
the  retainers;  this  saves  both  brake  pipe  and  auxiliary 
air.  Pick  out  places  where  sharp  curves  or  let-ups  in 
the  grade  slow  up  the  train  to  recharge  auxiliaries.  Air 
braking  on  a  long  hill  should  be  learned  on  that  particular 
hill — no  exact  rule  can  be  set  down;  the  instructions  here 
given  are  general.  To  test  the  brake  power  developed  on 
various  cars,  feel  of  the  wheels  at  the  bottom  of  the  hill 
when  possible;  cold  wheels  on  some  cars  and  hot  wheels 
on  others  show  unequal  braking  power.  Use  the  in- 
dependent engine  brake  while  recharging,  this  will  help 
hold  the  train. 

86.  Q.  What  is  the  difference  between  handling  a  long 
train  having  part  air  in  front  and  one  entirely  of  air? 

A.  A  great  difference.  It  requires  more  skill  and 
practice  to  make  a  good  stop  with  a  part  air  train  than 
with  a  full  air  train.  With  part  air  you  must  be  careful  to 
bunch  the  train  so  slack  will  run  up  easily  against  the 
air  brake  cars  before  setting  the  brake  very  tight;  this 
takes  some  seconds.  If  you  make  a  second  reduction 
before  the  rear  end  feels  the  effects  of  the  first  one,  the 
two  light  applications  make  one  heavy  one,  as  far  as  the 
shock  to  the  rear  cars  is  concerned.  When  backing  up, 
extra,  care  must- be  taken,  or  train  will  break  in  two  and 
merchandise  be  damaged  in  cars.  With  a  full  air  train 
the  first  reduction  of  brake  pipe  pressure  takes  so  much 
longer  to  start  all  the  triples  to  work  that  you  must  wait 
about  as  much  longer  after  the  brake  pipe  exhaust  stops 
flowing  before  making  a  second  reduction.  With  a  long 
all  air  train  and  new  empty  cars  with  short  piston  travel, 
or  coaches  on  the  rear  end,  it  is  a  good  rule  to  apply  the 
brakes  before  shutting  off  steam,  while  the  train  is 
stretched,  this  prevents  the  higher  power  brakes  at  the 


142  DOUBLE     HEADING 

rear  pulling  the  train  in  two.  The  brakes  are  longer  in 
releasing,  and  this  requires  more  time  after  releasing 
before  the  train  runs  free. 

87.  Q.     If  you  had  a  freight  train  with  "part  air"  cars 
in    operation    and    you    used    the    emergency    application, 
would  it  make  any  difference  whether  the  slack  was  out 
or  not?     In  case  there  was  a  shock,  on  what  part  of  the 
train  would  it  fall? 

A.  Using  the  emergency  brake  with  part  air  train 
always  sets  the  head  end  hard  and  solid;  if  slack  is  all 
run  up  against  the  engine  the  shock  is  not  as  great.  In 
any  case  the  rear  end  gets  all  the  damage;  the  weakest 
cars  and  draft  gear  behind  air  cars  suffer.  Empty  flat 
cars  next  the  air  are  likely  to  be  wrecked. 

88.  Q.     Which    engineer    should    handle   the   brakes    in 
double-heading,  and  what  should  the  other  engineer  do? 

A.  The  leading  engineer  should  handle  all  the  brakes 
when  double-heading,  as  he  is  the  only  man  who  can  see 
clearly  all  the  signals  and  the  condition  of  the  track  ahead, 
so  as  to  act  promptly  to  stop  the  train  when  necessary. 
The  following  engineer  should  shut  the  cut-out  cock 
under  his  brake  valve,  which  should  be  in  running  posi- 
tion with  the  1892  valve,  on  lap  with  the  H-5  valve,  on 
running  with  H-6,  keep  the  pump  running  and  a  full 
supply  of  air.  If  there  is  no  cut-out  cock,  place  brake 
valve  on  lap  so  no  air  can  get  into  the  brake  pipe  from 
his  main  reservoir  and  plug  up  train  pipe  exhaust  elbow, 
so  that  when  head  engineer  releases  brakes  the  brake 
pipe  air  will  not  escape  through  second  brake  valve.  If 
cut-out  cock  works  open  or  is  left  open  so  main  reservoir 
air  feeds  into  brake  pipe;  when  the  leading  engineer 
makes  a  service  reduction  the  air  from  the  following 
engine  will  hold  the  equalizing  piston  of  head  engine  up 
so  that  brake  pipe  exhaust  will  blow  strong  and  con- 
tinuously. If  head  man  is  sure  that  second  engine  is 
feeding  into  the  brake  pipe  when  brakes  are  to  be  set, 
he  should  go  to  emergency  at  once,  whistle  for  brakes, 
get  stopped  or  have  second  cut-out  cock  closed.  The 


BURSTED     AIR     HOSE  143 

emergency  port  of  first  brake  valve  will  take  air  out  of 
brake  pipe  faster  than  the  second  pump  and  reservoir  can 
supply  it,  especially  if  second  valve  is  on  running  position. 

When  testing  the  train  brakes  from  a  double-header, 
be  sure  that  main  reservoir  air  of  following  engines  is 
cut  out  from  brake  pipe  and  that  the  test  is  properly  made 
from  leading  engine. 

If  the  rules  allow  it  and  a  definite  arrangement  is  made 
between  the  engineers,  the  second  man  can  assist  in  releas- 
ing stuck  brakes  or  in  charging  auxiliaries  by  opening  his 
cut-out  cock  when  signaled  to  do  so  with  brake  valve  in 
full  release.  As  soon  as  train  is  moving  cut-out  cock 
should  be  shut  so  the  leading  engineer  can  stop  the  train 
at  once  if  necessary. 

The  rule  to  carry  brake  valve  on  running  position  with 
cut-out  cock  shut  varies  on  different  railroads.  One 
prominent  system  requires  that  the  brake  valve  be  carried 
on  emergency  position  so  that  in  case  of  necessity  brake 
will  go  on  at  once  if  cut-out  cock  is  opened.  Rules  of 
your  own  road  apply  in  this  case  to  position  of  valve. 

89.  Q.  What  would  you  do  if  an  air  hose  burst? 
How  would  you  know  it?  Should  you  have  extra  hose? 
Of  what  kinds? 

A.  Put  brake  valve  on  lap;  whistle  out  a  flag.  If  in 
a  dangerous  place  to  wait,  or  when  a  train  is  close  behind, 
shut  the  first  cock  ahead  of  bursted  hose;  let  off  brake 
on  head  end  from  engine;  bleed  the  cars  behind  bursted 
hose;  get  to  a  safe  place  and  replace  the  bursted  hose 
with  a  new  one.  If  with  bad  grades  or  all  air  train,  put 
in  a  new  hose  anyway,  if  possible.  It  would  be  known 
at  once,  because  brake  would  set;  black  hand  would 
drop  way  down ;  main  reservoir  pressure  would  also  run 
down  quickly.  Put  brake  valve  on  lap  to  save  your  main 
reservoir  air.  To  locate  the  bursted  hose  put  brake  valve 
on  running  position  just  so  you  will  keep  a  little  pressure 
in  the  hose  and  trainmen  can  hear  the  air  blowing  out  of 
bursted  hose  and  find  it. 

Extra  hose  chould  be  carried  on  engine,  one  of  each 


144  BREAK-IN-TWO 

kind  used.  Trainmen  should  have  a  standard  brake  hose, 
a  signal  hose  and  one  double-end  or  splice  coupling  to  use 
in  case  drawheads  or  coupling  of  cars  are  so  long  the 
regular  hose  and  couplings  will  not  meet  each  other. 

90  Q..  What  course  would  you  take  should  your  train 
break  in  two  and  set  the  brakes? 

A.  Put  brake  valve  on  lap,  shut  off  steam,  whistle  out 
a  flag,  shut  the  open  angle  cock  on  rear  end  of  last  car 
connected  to  engine,  let  off  brakes  on  head  section  from 
the  engine.  When  they  are  released  and  you  get  a  signal 
to  do  so,  back  up  to  rear  section;  after  coupling  up  to  it, 
if  brakes  cannot  be  let  off  from  engine,  bleed  a  few  of  the 
sticking  ones  at  back  end  of  train  until  train  can  be 
started.  Be  very  careful  to  shut  the  bleeder  as  soon  as 
air  begins  to  escape  from  triple  exhaust  port  or  you  will 
set  some  of  the  others,  and  that  will  hold  the  train  longer 
than  necessary.  All  air  bled  out  is  wasted ;  it  is  done  only 
to  save  time,  which  is  valuable  in  a  case  of  breaking  in 
two.  If  you  break  in  two  or  burst  a  hose  on  a  bad  grade, 
shut  both  angle  cocks  next  the  opening  in  hose,  this  will 
save  any  air  that  leaks  past  the  triples  into  the  brake 
pipe  and  hold  leaky  brakes  set  till  you  are  ready  to  release 
them  to  move  the  train. 

91.  Q.  Do  you  know  what  the  pressure  retaining 
valve  does?  And  how?  If  the  pipe  leading  to  this  valve 
should  break  off  would  you  plug  it?  If  you  did,  how 
would  it  affect  the  brake? 

A.  The  pressure  retaining  valve  holds  some  of  the 
compressed  air  in  the  brake  cylinder  after  the  triple  valve 
lias  moved  to  exhaust  position.  It  is  attached  to  exhaust 
port  of  triple  valve  by  a  piece  of  pipe  and  placed  where  it 
can  be  conveniently  reached  when  train  is  in  motion. 
When  set  to  operate,  its  handle  is  turned  up  to  a  horizon- 
tal position,  which  closes  the  direct  opening,  so  the  air 
goes  out  slowly  under  a  weighted  valve ;  and  then  passes 
out  of  the  case  of  valve  through  a  small  opening  so  air 
escapes  slowly.  When  pressure  falls  to  15  pounds  per 
square  inch  in  brake  cylinder,  this  valve  shuts  off  the 


PRESSURE   RETAINER  145 

escape  altogether  and  holds  the  air  in  there,  keeping  the 
brake  set  at  15  pounds ;  this  allows  the  auxiliary  reservoir 
to  be  recharged  to  full  pressure  again.  It  is  used  on  long, 
steep  grades.  If  the  pipe  leading  from  the  triple  valve 
exhaust  to  the  retainer  was  broken  off  that  retainer  would 
be  useless.  The  pipe  should  never  be  plugged,  as  that 
brake  would  not  let  off  at  all ;  there  would  be  no  way  for 
the  air  to  get  out  of  the  brake  cylinder. 

The  old  style  retainers  held  15  pounds;  there  are 
other  styles  now  made  with  heavier  weights  to  hold 
more.  A  later  style  has  two  weights,  by  placing  the 
handle  in  one  position  both  weights  come  on  the  valve, 
in  another  position  only  one  weight  bears  on  the  valve, 
this  varies  the  pressure  at  the  will  of  the  trainman,  who 
turns  up  the  handle  with  50  pounds  as  the  maximum. 

92.  Q.  When  air  blows  out  steadily  from  the  pressure 
retaining  valve,  should  it  be  closed  or  left  open? 

A.  Left  open  by  all  means.  The  air  that  blows  out 
there  comes  from  a  leak  in  the  triple  valve;  shutting  the 
pressure  retainer  only  stops  air  coming  out  there  and 
sets  the  brake,  or  if  leak  is  a  small  one,  makes  it  go  out 
through  the  leakage  groove  in  the  brake  cylinder.  If 
pressure  retainer  is  turned  up,  even  if  the  brake  does  not 
set  right  off,  it  will  stay  set  when  engineer  sets  it  and 
tries  to  let  it  off.  Never  turn  up  retainers  unless  you 
want  to  hold  the  brake  set  the  next  time  engineer  releases 
it.  If  the  pressure  retainer  is  broken  off  or  the  pipe  lead- 
ing to  it  from  triple  is  broken  or  leaking  badly,  it  does 
not  affect  the  operation  of  the  brake  in  any  way,  except 
that  the  retainer  cannot  be  used  on  that  car.  If  retainer 
is  broken  off  and  pipe  plugged  the  brake  cannot  be  re- 
leased at  all  from  the  engine,  as  there  is  no  way  for  air 
to  escape  from  triple  valve  exhaust.  If  there  is  a  leak 
in  pipe  from  triple  valve  to  retainer,  the  retainer  is  of  no 
use,  as  air  will  escape  from  the  pipe  at  leak  when  retainer 
is  set  to  work.  Sometimes  the  pipe  to  pressure  retainer 
gets  stopped  up  so  air  cannot  get  through  it,  in  which 
case  the  brake  will  set  once  and  not  release  till  bled  off. 


146  AIR    SIGNAL 

It  is  not  unusual  to  find  nests  of  insects  in  the  pipe  right 
at  retainer.  Pressure  retainers  are  put  on  all  freight 
cars  used  in  interchange  service.  Very  few  coaches  have 
them,  only  those  running  on  mountain  roads.  Sleepers 
and  official  cars  usually  have  retainers.  They  are  used 
on  level  roads  extensively  to  hold  the  slack  bunched  in  a 
long  train;  in  this  case  they  are  usually  applied  to  the 
driver  brake  triple  valve  and  located  in  the  cab  in  easy 
reach  of  the  engineer,  the  straight  air  brake  and  ET 
brake  are  much  better.  They  are  valuable  aids  in  making 
smooth  stops  with  freight  trains  at  water  plugs. 

93.  Q.  How  does  the  air  signal  operate?  If  the  air 
signal  on  the  engine  whistled  each  time  you  released  the 
brakes,  what  would  be  the  trouble?  If  the  whistle  blows 
frequently  when  not  in  use,  what  is  the  matter?  If  it 
blows  one  long  blast?  If  the  whistle  is  weak  on  engine 
will  it  usually  help  it  to  blow  out  the  signal  hose  on  the 
rear  of  tender? 

A.  The  air  signal  valve  on  the  engine  is  operated  by 
a  reduction  of  pressure  made  in  the  signal  line.  This 
signal  line  is  supplied  with  air  from  the  main  reservoir 
which  passes  through  a  reducing  valve  set  at  a  much 
lower  pressure  than  the  standard  braking  pressure,  so  the 
operation  of  the  brake  will  not  interfere  with  the  opera- 
tion of  the  signal.  The  opening  through  the  reducing 
valve  is  choked  down  to  restrict  the  flow  of  air  into  the 
signal  pipe  and  allow  a  reduction  to  be  made  in  its 
pressure.  This  reduction  must  be  a  sudden  one,  like  an 
emergency  reduction  for  the  triple  valve,  or  the  reducing 
valve  will  feed  air  into  the  signal  pipe  as  fast  as  it  is 
taken  out  at  the  car  discharge  valve.  When  the  pressure 
is  reduced  in  the  signal  line  at  the  car  discharge  valve 
and  this  reduction  extends  to  the  signal  valve,  it  affects 
the  pressure  in  chamber  A  above  the  diaphram  12  first, 
so  that  the  pressure  in  B  under  the  diaphram  lifts  it  up, 
also  raising  the  discharge  valve  10  off  the  seat  at  7,  which 
allows  the  air  to  pass  to  whistle. 

If  the  diaphram  gets  bagged  down,  the  pressure  in  B 


AIR     SIGNAL    DEFECTS  .  147 

will  raise  the  baggy  part  of  the  rubber  and  valve  will  not 
raise  off  the  seat. 

The  stem  of  valve  10  has  the  sides  flattened,  except 
for  a  short  distance  at  the  top,  where  it  enters  bushing  9, 
when  this  stem  rises  the  flattened  part  comes  above  bush- 
ing 9,  and  air  from  B  also  goes  to  the  whistle,  this 
reduces  the  pressure  in  B.  When  the  car  discharge  valve 
is  closed  and  the  signal  line  pressure  is  increased  by  the 
reducing  valve,  as  the  stem  of  10  makes  a  moderately 
close  fit  in  the  top  of  bushing  9,  air  passes  into  B  slowly 
while  recharging.  Chamber  A  is  therefore  charged  up 
first  so  diaphram  is  sure  to  set  valve  10  promptly. 

If  the  fit  of  the  stem  at  the  top  of  the  bushing  is  too 
loose  the  valve  is  liable  to  rise  on  its  seat  so  the  signal 
will  "repeat"  and  give  more  than  one  blast  for  each  pull 
of  the  car  discharge  valve. 

This  fit  must  be  exact  or  the  signal  valve  will  not 
always  respond  on  both  long  and  short  trains  to  the 
proper  reductions. 

If  an  air  signal  whistles  each  time  brake  is  released 
with  standard  braking  pressure,  it  is  a  sign  the  reducing 
valve  is  dirty  and  stuck  open,  so  air  goes  back  into  main 
reservoir  from  signal  line  each  time  main  reservoir  press- 
ure is  reduced  in  recharging  train.  In  this  case  signal 
line  has  main  reservoir  pressure.  Clean  the  reducing 
valve  before  the  air  signal  hose  bursts.  The  whistle  will 
give  a  shrill  sound  if  pressure  is  too  high.  If  the  spring 
in  the  old  style  reducing  valve  over  diaphram  is  too  stiff 
it  will  do  this.  The  improved  reducing  valve  is  regulated 
for  the  proper  pressure  in  the  same  manner  as  the  feed 
valve  on  F-6  brake  valve.  The  reducing  valves  are  set  at 
about  forty-five  now ;  the  old  valves  were  set  at  twenty- 
five  pounds.  This  is  so  as  to  carry  a  lower  pressure  in 
signal  line  than  is  used  to  operate  the  brake.  To  test 
the  pressure  at  which  reducing  valve  operates,  shut  off 
the  pump,  reduce  the  main  reservoir  about  five  pounds 
at  a  time  through  brake  valve  till  the  signal  whistle  blows; 
this  shows  that  the  reducing  valve  is  held  open  by  the 


Signal  Valve, 


Pressure  Reducing  Valve* 


Improved  Reducing  & 
Valve. 


AIR    SIGNAL    DEFECTS  149 

spring  so  air  can  pass  from  signal  pipe  into  main  reser- 
voir. If  the  signal  whistle  blows  frequently  when  not  in 
use,  there  is  a  leak  somewhere,  which  the  jar  of  the 
engine  may  open  for  an  instant,  or  the  reducing  valve 
may  be  out  of  order.  If  it  sticks  a  little  in  its  seat,  as  in 
cold  weather,  a  very  small  leak  will  cause  the  whistle  to 
give  a  strong  blast — or-  a  jar  may  unseat  signal  valve. 
When  it  blows  one  long  whistle  some  of  the  valves  on 
engine  are  stuck,  or  the  car '  discharge  valve  is  opened  a 
second  and  third  time  before  the  whistle  stops  blowing 
the  first  blast;  the  pressure  in  signal  line  must  equalize 
each  time  between  the  blasts  to  make  it  work  accurately. 
If  the  stem  10  makes  too  close  a  fit  in  bushing  9  the 
whistle  will  give  only  one  blast  for  two  or  more  reduc- 
tions of  signal  line  pressure,  or  a  very  small  leak  in  the 
signal  line  will  cause  signal  valve  to  operate  at  intervals, 
when  a  proper  fit  would  allow  it  to  work  properly.  If 
the  whistle  bell  works  loose  so  it  does  not  make  a  clear 
sound,  or  is  located  near  partly  opened  windows  so  a 
strong  draft  of  air  blows  across  it,  when  train  is  run- 
ning fast,  the  sound  will  be  very  weak.  Blowing  out 
the  signal  hose  at  rear  of  tender  gives  all  the  valves  a 
chance  to  make  a  full  opening  and  clean  out  the  dirt. 
To  test  the  signal  line  for  leaks,  shut  the  cut-out  cock  at 
the  reducing  valve;  if  the  signal  line  leaks,  the  whistle 
will  blow  as  soon  as  the  leak  reduces  the  pressure.  On  a 
double  header  both  whistles  should  sound  for  the  same 
reduction  of  signal  line  pressure.  If  they  do  not,  close 
the  cock  in  the  reducing  valve  on  the  following  engine 
so  only  one  reducing  valve  will  be  feeding  into  the  train 
signal  line  and  thus  allow  the  car  discharge  valve  to  do 
its  work  properly.  With  both  reducing  valves  cut  in  the 
signal  valve  will  not  always  operate  on  the  leading 
engine  when  the  brake  pipe  reduction  is  made  from  the 
rear  cars  of  a  long  train. 

With  the  ET  locomotive  brake,  the  same  reducing 
valve  is  used  for  the  independent  brake  valve  and  the  air 
signal  system.  There  is  a  non-return  check  valve  in  the 


150  TRAINMEN'S  QUESTIONS 

signal  pipe  so  the  air  can  not  get  back  from  the  signal  pipe 
when  the  independent  valve  takes  air  to  apply  the  brake 
as  it  would  sound  the  whistle.  This  valve  is  shown  at 
question  37. 


FOR    TRAINMEN 

94.  Q.     When    coupling    the    engine    to    an    air    brake 
train,     equipped     with     quick-action     triples    and    already 
charged  with  air,  which  angle  cock  should  be  opened  first  * 

A.  The  one  on  engine  always,  so  as  to  fill  the  hose 
from  engine.  If  cock  on  car  is  opened  first,  the  train 
brake  is  liable  to  set  with  emergency  action.  Get  in  the 
habit  of  opening  the  cock  on  engine  first,  whether  train  is 
charged  or  empty. 

95.  Q.     When    coupling    an    empty    car    to    other    cars 
already  charged  and  working,  how  should  the  angle  cocks 
be  opened? 

A.  Open  the  one  on  empty  car  first,  so  the  empty 
brake  pipe  and  empty  hose  will  be  connected.  Then  open 
the  angle  cock  on  the  charged  car  slowly  so  the  pressure 
in  brake  pipe  will  not  be  reduced  any  faster  than  the 
engine  can  supply  it.  This  will  prevent  the  brakes  setting 
on  head  end  of  train,  which  they  will  do  with  emergency 
action  if  angle  cock  is  opened  suddenly.  A  little  practice 
will  teach  you  the  advantage  of  this.  This  applies  to 
coupling  up  the  air  on  a  train  that  has*  been  separated  to 
open  public  crossings.  When  coupling  to  cars  on  a  side 
track  that  are  going  with  your  train,  make  the  air  brake 
connections  also,  so  the  auxiliaries  will  be  charging  ready 
for  operating  the  brake  while  you  are  getting  out  on  the 
main  track,  this  will  save  time  in  testing  the  brakes,  as 
they  will  be  ready  when  train  is  all  coupled  up.  When 
air  braked  cars  are  to  be  set  on  a  coming  train,  charge 
these  cars  with  air  from  the  engine  used  to  place  them 
on  the  train,  it  saves  delay. 

96.  Q.     If  an  angle  cock  at  head  end  of  train  is  only 


152  MAKING    UP    A    TRAIN 

partly  opened  or  there  is  an  obstruction  in  the  brake  pipe, 
how  will  it  affect  the  operation  of  the  brake? 

A.  The  brake  can  be  set  with  service  application,  but 
it  releases  very  slowly  as  the  air  does  not  get  back  fast 
enough  to  move  all  the  triple  valves  to  release  promptly, 
and  any  triples  with  defective  packing  rings  back  of  the 
obstruction  will  be  sure  to  stick.  With  angle  cock  on 
tender  partly  open,  you  cannot  always  get  the  emergency 
action  of  the  brake.  When  passing  over  the  top  of  the 
train,  angle  cocks  can  be  inspected,  as  they  are  generally 
far  enough  outside  the  end  of  car  so  the  handles  are 
visible  from  top  of  car.  When  cocks  are  wide  open  the 
handles  are  exactly  over  the  hose.  The  old  style  plug 
shut-off  cocks  come  in  the  straight  pipe  just  under  the 
end  of  car  and  cannot  be  seen  when  passing  over  the  cars. 

97.  Q.  Can  an  air  brake  train  be  made  up  so  it  will 
be  impossible  to  get  the  emergency  action  of  the  brake 
from  the  engineer's  brake  valve? 

A.  If  there  are  four  cars  with  the  brakes  cut  out  at 
cross-over  near  triples,  or  four  cars  with  brake  pipe  only, 
or  with  plain  triples,  next  to  the  engine,  the  reduction  of 
air  pressure  in  brake  pipe  will  be  so  gradual  on  the  fifth 
car  that  you  cannot  get  the  emergency  application  of  the 
quick-action  triples.  It  takes  a  sudden  reduction  at  the 
first  quick-action  triple  to  get  the  emergency.  Switch  the 
plain  triples  among  the  quick-actions;  you  may  need  them 
to  make  a  sudden  stop  in  an  emergency. 

98i  Q.  Why  should  train  brakes  be  tested  before 
leaving  a  terminal  or  any  point  where  the  make-up  of  the 
train  has  been  changed?  How  should  this  test  be  made? 

A.  So  you  will  know  before  starting  out  that  the 
brakes  will  work  when  necessary.  After  coupling  the 
engine  on  the  train  the  pressure  should  be  equalized  in  all 
the  auxiliaries,  so  all  the  brakes  will  set  at  the  same 
reduction  of  brake  pipe  pressure.  The  pressure  should  be 
70  pounds  in  the  auxiliaries  in  order  to  get  a  full  applica- 
tion of  the  brakes  to  test  the  piston  travel.  While  the 
engine  is  charging  the  train  to  standard  pressure,  which 


TESTING    A    TRAIN  153 

will  take  some  time  on  a  long  train,  a  careful  inspection 
should  be  made  for  leaks,  and  to  see  that  all  brake  pipe 
cocks,  cross-over  cocks  and  pressure  retainer  handles,  are 
in  the  proper  position  to  operate  all  the  brakes.  When 
standard  pressure  is  reached  the  brakes  should  be  applied 
from  the  engine  that  is  to  handle  them  with  a  full  service 
application  made  in  the  same  manner  as  when  making  a 
station  stop  of  the  moving  train.  The  trainmen  or  in- 
spector will  then  examine  each  brake  to  see  that  it  is  set 
with  not  less  than  five  nor  more  than  nine  inches  piston 
travel.  When  all  brakes  are  inspected,  if  they  are  set 
properly,  he  will  give  a  signal  to  the  engineer  to  release 
brakes  and  examine  each  brake  to  see  that  they  have 
released  properly.  If  any  brakes  require  adjustment  of 
piston  travel  it  must  then  be  done.  Be  sure  to  close  the 
cut-out  cock  in  the  cross-over  while  doing  any  work  on 
the  levers  or  shoes,  so  the  brake  will  not  set  and  injure 
the  workman,  opening  it  when  adjustment  is  made.  If 
pressure  retainers  are  to  be  used,  they  should  be  tested 
after  the  piston  travel  is  tested,  by  applying  the  brakes 
with  a  10  pound  reduction,  with  retainer  handles  turned 
up.  As  soon  as  the  retainers  are  quiet,  go  along  and  turn 
down  the  handles,  the  air  should  blow  out  from  each  of 
them,  which  shows  that  they  hold  the  pressure  in  cylinders. 
Long  freight  trains  can  be  tested  by  two  inspectors,  one 
at  each  end  working  towards  the  middle  of  the  train  till 
they  meet.  On  passenger  trains  equipped  with  the  air 
signal,  the  signal  for  releasing  after  a  test  should  be 
given  with  the  car  discharge  valve  from  the  rear  plat- 
form of  the  last  car. 

99.  Q.  How  can  the  piston  travel  on  a  freight  car 
be  tested  and  then  taken  up  the  proper  length  when  car 
is  not  charged  with  air  and  brake  operated? 

A.  See  that  the  push  rod  going  from  piston  to  brake 
cylinder  lever  is  clear  in  against  the  bottom  of  piston 
sleeve.  Make  a  mark  on  the  push  rod  even  with  the  end 
of  the  sleeve.  Set  the  brake  by  hand  as  tight  as  possible, 
with  a  club  if  necessary;  the  distance  push  rod  is  pulled 


154  DEFECTIVE    BRAKE 

out  of  the  sleeve  is  the  piston  travel.  There  is  generally 
over  an  inch  more  piston  travel  when  car  is  moving  than 
when-  standing;  it  is  more  with  heavy  braking  power  on 
a  car  than  with  light.  The  piston  travel  on  an  empty 
car  may  be  very  short,  say  four  inches,  and  when  loaded 
the  same  car  may  have  nine  inches.  When  testing  from 
the  engine,  have  the  brakes  set  with  full  service  applica- 
tion, so  you  will  get  full  piston  travel. 

100.  Q.  If  the  brake  sets  tight  when  you  are  charging 
the  auxiliary  reservoir  with  air  when  first  coupling  the 
hose  to  another  car,  should  you  cut  out  that  brake? 

A.  If  it  is  a  quick-action  triple  it  is  a  sign  that  air 
leaks  through  some  of  the  joints  or  valves  in  the  triple 
into  the  brake  cylinder.  Have  the  engineer  set  and  release 
the  brake  suddenly,  once  or  twice;  if  there  is  dirt  on  the 
rubber  seat  of  the  emergency  valve  which  causes  the 
trouble,  it  will  sometimes  blow  it  off;  if  it  does  not  make 
the  brake  work  all  right,  very  likely  some  of  the  gaskets 
are  leaking  badly;  in  such  a  case  cut  it  out  and  bleed  it. 
With  the  freight  brake  there  may  be  a  leak  in  the  pipe 
from  the  triple  valve  to  the  brake  cylinder  which  passes 
through  the  auxiliary  reservoir,  nothing  can  be  done  on 
the  road  for  a  leak  of  this  kind  but  cut  out  the  brake. 
Most  always  in  these  cases  the  air  blows  out  of  exhaust 
port  or  at  the  pressure  retaining  valve.  With  the  plain 
triple  the  plug  cock  in  triple  may  be  turned  out  for 
"straight  air."  This  will  allow  the  air  to  go  direct  from 
brake  pipe  to  brake  cylinder;  none  of  it  will  come  out  of 
exhaust  port,  as  the  triple  is  cut  out  from  brake  pipe  and 
cylinder.  In  this  case  cut  it  in  for  automatic.  If  the 
handle  is  gone,  or  put  on  wrong,  examine  the  marks  on 
the  end  of  plug  which  show  which  way  the  air  openings 
are  and  you  will  know  which  way  to  turn  the  plug.  If 
this  plug  cock  leaks,  the  air  can  get  past  it  from  brake 
pipe  to  brake  cylinder.  If  brake  will  not  work  after  one 
or  two  applications,  cut  it  out.  With  all  plain  triples  the 
brake  should  be  released  first,  although  the  plain  triple 
used  on  freight  equipment  is  built  to  bleed  the  brake 


PISTON    TRAVEL  155 

cylinder  when  brake  is  cut  out.  Sometimes  this  bleed 
hole,  which  is  in  one  side  of  plug  cock  in  the  plain  freight 
triple  valve,  gets  stopped  up,  in  which  case  it  may  be 
necessary  to  let  all  the  air  out  of  the  brake  pipe — set 
this  triple  for  straight  air  which  will  bleed  brake  cylinder, 
after  which  cock  in  triple  can  be  placed  in  cut  out 
position. 

101.  Q.  If  the  piston  travel  is  too  long  or  too  short 
what  effect  does  it  have  on  the  brake  as  to  its  holding 
power? 

A.  If  it  is  too  short  it  will  not  cover  the  leakage 
groove,  and  air  will  leak  out  of  cylinder ;  it  must  travel 
three  inches  to  cover  this  groove.  If  it  is  too  long  it  will 
strike  the  cylinder  head,  which  will  get  the  force  instead 
of  the  brake  shoes;  it  must  travel  twelve  inches  to  do  this. 
All  brake  pistons  on  coach,  freight  and  tender  equipment 
of  standard  gage  have  12-inch  piston  stroke,  but  should 
not  have  over  8  or  9  inches  piston  travel.  The  piston 
travel  should  be  adjusted  equally  so  the  braking  power 
will  be  equal  on  all  cars.  Unequal  piston  travel  gives 
unequal  braking  power.  This  is  the  cause  of  many  severe 
shocks  to  long  trains  when  first  applying  the  brakes,  and 
still  more  severe  shocks  when  releasing  the  brakes  at  a 
slow  speed.  For  instance,  if  some  of  the  brakes  have  only 
five  inches  piston  travel,  when  the  engineer  makes  the 
first  reduction  of  brake  pipe  pressure  to  apply  the  brakes, 
those  with  short  travel  will  set  hard  enough  to  take  up  the 
slack  of  train  quicker  than  the  other  brakes  with  long 
piston  travel.  A  first  reduction  in  applying  the  brakes  is 
at  least  7  pounds,  less  than  this  will  not  apply  all  the 
brakes  on  a  long  train.  This  will  give  a  pressure  of 
23  pounds  on  the  piston  with  5-inch  travel,  8  pounds  on 
one  with  9  inches  travel,  one  with  10  inches  travel  will 
not  show  any  pressure  at  all,  the  shoes  will  just  come 
nicely  up  to  the  wheels.  A  few  short  travel  brakes  can 
give  serious  shocks  in  a  train  that  are  plainly  felt  at  the 
rear  end. 


156  LEAKY   PACKING   LEATHER 

102.  Q.     If   air   blows   past   piston   packing    so    freight 
brake  leaks  off,  can  it  be  fixed  on  the  road? 

A.  Sometimes  this  is  from  want  of  oil  in  the  cylinder; 
if  the  oiling  plug  near  back  cylinder  head  where  it  makes 
a  joint  with  cast  iron  auxiliary  reservoir  is  taken  out  and 
four  or  five  tablespoonsful  of  black  oil  put  in,  it  will  soften 
the  packing  so  it  will  be  tight.  The  piston  sleeve  should 
then  be  turned  around  one-half  turn  to  bring  the  softened 
packing  to  the  top  of  the  cylinder.  This  should  be 
attended  to  by  car  inspectors,  but  is  not  always  done.  In 
no  case  should  oil  or  water  be  put  in  the  hose  and  be 
blown  back  into  the  triple  with  the  air.  It  will  carry  the 
dust  and  sand  back  in  the  pipe  towards  the  triple;  this 
stops  up  the  strainers,  and  if  any  gets  by  the  strainers  it 
spoils  the  rubber  seat  of  the  emergency  valve,  and  cuts 
the  triple  to  pieces  very  fast.  Putting  oil  in  the  hose  will 
destroy  the  efficiency  of  the  brake  in  very  short  time. 

103.  Q.     How  can   the   air   signal   whistle  be   operated 
from  the  cars  most  successfully? 

A.  By  allowing  just  enough  air  to  escape  at  the  car 
discharge  valve  to  reduce  the  air  signal  line  pressure  clear 
to  signal  valve  on  engine,  so  that  it  will  operate  promptly, 
then  allowing  car  discharge  valve  .to  close  and  remain 
closed  till  signal  line  is  recharged  to  standard  pressure;, 
this  sometimes  takes  two  seconds.  A  heavier  reduction 
with  a  longer  interval  between  pulls  is  needed  for  a  very 
long  train  than  a  short  one.  The  whistle  will  give  only 
one  blast  if  the  car  discharge  valve  is  opened  a  second 
and  third  time  before  the  whistle  stops  blowing  the  first 
time. 

If  you  make  a  second  and  third  reduction  before  the 
reducing  valve  on  engine  has  had  time  to  charge  signal 
line  to  standard  pressure,  the  second  and  third  blasts  of 
whistle  will  be  very  weak;  in  cold  weather  the  reducing 
valves  do  not  always  work  perfectly.  Sometimes  when  a 
car  discharge  valve  is  opened,  a  sufficient  amount  of  air 
will  seem  to  blow  out  there,  but  on  account  of  an 
obstruction  near  the  brake  pipe  Tee  under  car  it  does  not 


AIR     SIGNAL  157 

reduce  the  pressure  enough  at  the  engine  to  operate  the 
signal  valve,  and  the  whistle  cannot  be  operated  from  that 
car  when  it  works  from  other  cars.  If  the  whistle  blows 
once  when  engine  is  coupled  to  train  and  cannot  be 
sounded  afterward,  look  for  a  bad  leak  near  rear  end  of 
train. 

If  the  whistle  cannot  be  sounded  from  any  cars  back 
of  a  certain  car,  the  cock  in  back  end  of  that  car  is  shut, 
or  brake  pipe  is  stopped  up  so  you  cannot  make  a  sudden 
enough  reduction  there  to  affect  the  signal  valve  on  the 
engine.  If  one  blast  of  the  whistle  is  used  to  start  the 
train  without  using  any  additional  signal,  remember  that 
one  blast  of  the  whistle  can  be  given  (without  opening  car 
discharge  valve)  when  you  do  not  want  the  train  started. 
For  instance,  if  the  signal  hose  has  been  uncoupled  (with- 
out the  knowledge  of  the  engineer)  for  any  purpose;  when 
the  cock  is  opened  enough  air  goes  into  empty  hose  to 
sound  the  whistle,  giving  signal  to  start  the  train  before 
the  man  coupling  hose  can  get  out  from  between  coach 
platforms.  Other  causes  may  cause  the  whistle  to  give 
one  blast  when  not  intended,  therefore  it  is  not  always 
safe  to  use  one  blast  of  the  whistle  when  standing  still, 
to  start  the  train. 

104.  Q.     If  hand  brakes  are  used  on  part  air  train,  on 
which  cars  should  they  be  used? 

A.  On  the  cars  next  behind  the  air  braked  cars  so  the 
hand  brakes  will  hold  these  cars  and  prevent  slack  run- 
ning out  of  rear  cars  when  air  brakes  are  released.  In 
case  of  an  emergency,  all  hand  brakes  should  be  set  on 
cars  that  do  not  have  air  brakes  working.  Care  should 
be  taken  that  hand  brakes  are  released  on  rear  end  of  a 
part  air  train  first,  air  brakes  last,  when  running  forward 
and  in  the  reverse  manner  when  backing  a  train. 

105.  Q.     On  an  air  braked  passenger  train  in  case  the 
engineer  whistles  for  brakes  what  is  the  trainmen's  duty? 

A.  Open  tthe  conductor's  valve  first.  An  angle  cock 
may  be  closed  which  prevents  the  engineer  applying  all 
the  brakes.  If  the  air  escapes  freely  and  the  brake  goes 


158  LEAKING   BRAKES 

on,  let  hand  brakes  alone.  If  no  air  escapes  from  brake 
pipe  the  brake  may  have  already  been  set.  Try  the  hand 
brakes  last,  if  the  brake  is  set  with  air  pressure  you  can 
not  move  it  by  hand  on  any  cars  where  the  hand  brake 
sets  opposite  to  the  air  brake.  If  it  is  not  set  with  air 
you  can  set  it  by  hand,  the  air  may  have  leaked  out  of 
cylinder. 

106.  Q.     How    do    leaks    affect    the    operation    of    the 
brake  on  a  car  or  coach? 

A.  If  the  brake  pipe  leaks  the  brake  will  continue  to 
set  tighter  after  the  first  reduction  till  full  set.  Leaks  at 
the  gaskets  in  the  couplings  can  be  stopped  by  putting 
in  new  gaskets.  Do  not  pound  the  guard  arms  of  the 
couplings  as  that  will  likely  cause  the  hose  to  tear  off 
in  a  break-in-two.  This  leak  affects  a  single  car  or  a 
short  train  more  than  a  long  train,  as  a  short  brake  pipe 
has  less  volume  of  air  to  leak  out. 

A  leak  from  the  brake  pipe  past  the  seat  of  the  emer- 
gency valve  will  allow  the  brake  pipe  air  to  equalize  with 
the  brake  cylinder  when  the  brake  is  applied  so  the  triple 
slide  valve  has  closed  the  exhaust  port;  this  may  stick 
this  brake  especially  if  the  triple  piston  packing  ring  also 
leaks. 

Any  leak  from  the  auxiliary  which  makes  that  press- 
ure less  than  the  brake  pipe  will  move  the  triple  to  ex- 
haust position;  the  air  in  cylinder  will  escape  through 
exhaust.  With  a  leaky  packing  leather  the- air  will  blow 
past  it,  coming  out  around  the  piston  rod  or  sleeve;  none 
will  come  out  of  the  exhaust. 

107.  Q.     Where  should  you  look  for  the  trouble  if  the 
brake   applied   properly,   but   would   not   release? 

A.  Very  likely  the  pressure  retaining  valve  was 
closed;  examine  it  first  to  be  sure  it  is  open.  On  some 
sleepers  and  official  cars  both  the  triple  valve  and  re- 
tainer are  concealed  by  the  reservoirs  and  lockers,  so  it  is 
necessary  to  hunt  them  up  beginning  with  the  triple 
exhaust,  and  if  any  pipe  is  attached  following  it  up.  If 
the  retainer  pipe  is  stopped  up  or  plugged  no  air  can  come 


STICKING   BRAKES  159 

out  of  triple  exhaust.  In  cold  weather  the  water  from 
drip  valves  of  steam  heated  cars  may  splash  over  the 
exhaust  ports  of  triple  valve  and  freeze  on;  this  may 
stop  up  the  exhaust. 

Levers  or  rods  may  catch  on  bolt  heads  or  other  pro- 
jections under  the  car  and  hold  the  brake  after  the  air 
has  exhausted  from  cylinder.  If  the  release  spring  in 
cylinder  is  broken  the  piston  will  not  move  back.  Stopped 
up  strainers  at  the  triple  have  been  known  to  prevent 
release  of  brake;  air  would  pass  out  of  valve,  but  could 
not  return  quickly. 

108.  Q.     In    case    a    brake    is    noticed    to    be    sticking 
regularly,  can  you  help  it  to  release  at  the  same  time  the 
others  do? 

A.  Short  piston  travel  may  cause  this  trouble.  By 
extending  the  piston  travel  it  will  lower  the  auxiliary 
pressure  on  a  full  application  so  the  triple  is  more  likely 
to  move  up  promptly.  As  brakes  are  more  apt  to  stick  on 
the  rear  of  a  long  train  than  when  next  the  engine,  this 
car  can  be  set  ahead  if  necessary  to  use  its  brake. 

Leaky  triple  packing  rings  and  choked  strainers  will 
also  cause  this  trouble.  Better  cut  out  the  brake  than 
risk  spoiling  the  wheels.  Report  this  defect  to  the  proper 
party. 

109.  Q.    How  does  the  water  raising  system  used  on 
Pullman  cars  operate? 

A.  This  system  has  so  many  modifications  and  is  so 
complicated  that  a  full  description  cannot  be  given  here. 
There  is  an  air  reservoir  which  is  charged  with  the  air  up 
to  brake  pipe  pressure,  sometimes  directly  from  the  brake 
pipe ;  at  other  times  from  the  brake  auxiliary  reservoir ; 
the  latest  method  being  to  take  air  from  the  brake  aux- 
iliary. To  regulate  the  flow  of  air  into  this  air  storage 
reservoir  there  is  a  governor  and  non-return  check  valve; 
the  latest  pattern  of  which  is  here  shown.  The  governor 
operates  exactly  like  an  air  pump  governor  and  should 
be  set  at  60  pounds  so  it  will  not  interfere  with  the  air 
brake  pressure  when  that  is  below  60  pounds.  In  this 


160 


WATER  PRESSURE  REGULATOR 


same  valve  is  a  non-return  check  38,  to  prevent  air 
coming  back  from  the  air  storage  reservoir,  the  stem  of 
which  is  made  a  neat  fit  at  h  so  the  air  will  feed  past 
it  slowly  and  not  take  air  too  fast.  Between  the  air 

WATER,PRESSURE  GOVERNOR 
VALVE. 


TO  AIR  STORAGE 
RESERVOIR 

X 


storage  reservoir  and  the  water  reservoirs  is  a  reducing 
valve  similar  to  the  one  used  with  the  air  signal,  set  at 
20  pounds,  which  pressure  is  sufficient  to  give  a  good  flow 


WATER     RAISING     SYSTEM  .  161 

of  water  to  the  basins.  If  this  reducing  valve  is  set  at 
too  high  a  pressure  or  gets  dirty  or  stuck  open  so  it  does 
not  operate,  the  full  pressure  of  the  storage  reservoir  will 
be  in  the  water  tanks,  which  not  only  uses  too  much  air, 
but  is  liable  to  splash  the  water  all  over  the  basins  when 
faucet  is  opened.  The  pressure  in  the  water  tanks  oper- 
ates this  reducing  valve.  When  the  tanks  are  to  be  re- 
filled the  air  supply  is  shut  off,  that  in  the  tanks  is 
allowed  to  escape  and  water -'put  in.  When  air  comes  out 
into  the  basins  with  the  water  it  is  a  good  sign  '•  the  water 
is  nearly  gone.  If  no  water  or  air  comes  out  when  you 
are  sure  there  is  a  proper  air  pressure,  examine  the 
numerous  cocks  to  see  if  any  of  them  are  closed.  As 
the  cars  are  not  all  piped  exactly  alike  it  is  usually  neces- 
sary to  {race  the  pipes  up  and  locate  the  stop  cocks  and 
valves  when  making  an  inspection.  There  are  also  heat- 
ing pipes  connected  with  the  devices  of  the  water  raising 
system  to  prevent  freezing  up.  Gages  are  usually  located 
up  in  the  cars  which  show  the  air  pressure  in  the  storage 
reservoir  and  water  tanks,  70  in  the  former  after  charging 
fully,  and  20  in  the  water  tanks.  Suitable  cocks  under 
control  of  the  porters  are  provided  to  open  or  close  the 
passage  of  air  from  brake  system  to  the  water  raising 
system  with  a  code  of  rules  for  operating  these  cocks. 

110.  Q.  How  does  this  water  raising  system  affect  the 
operation  of  the  brake? 

A.  When  air  is  passing  from  brake  pipe  or  auxiliary 
to  air  storage  reservoir  it  takes  a  little  time  to  charge 
the  storage  reservoir.  If  at  that  time  brake  is  applied 
as  when  making  a  terminal  test  of  train  brakes,  air  pass- 
ing from  the  brake  pipe  will  set  the  brakes  tighter;  if  it 
goes  from  the  brake  auxiliary  it  will  likely  release  that 
brake,  especially  if  set  with  a  light  application.  If  the 
non-return  check  valve  leaks  back  after  air  storage  reser- 
voir is  fully  charged,  this  air  can  flow  in  the  brake  pipe 
if  so  connected  and  release  all  the  train  brakes.  If  the 
connection  is  made  to  the  brake  auxiliary,  a  leaky  check 
valve  will  allow  the  volume  of  the  storage  reservoir  to 


162  WATER    RAISING     SYSTEM 

be  added  to  that  of  the  auxiliary  and  skid  the  wheels  on 
a  full  application.  If  all  the  stop  cocks  are  not  properly 
operated  and  the  valves  in  good  order  the  work  of  the 
brake  may  be  interfered  with,  which  shows  that  it  is 
absolutely  necessary  that  they  should  be  inspected  at 
regular  intervals  by  competent  men  and  be  maintained  in 
proper  order.  If  the  governor  which  restricts  the  flow 
of  air  from  the  brake  system  is  in  perfect  order  and  set 
at  the  proper  pressure,  unless  a  large  amount  of  air  is 
used  by  the  water  system,  the  operation  of  the  brake 
will  not  be  materially  affected.  If  air  is  taken  from  the 
brake  system  during  the  application  of  the  brake  it  is 
sure  to  affect  the  work  of  the  triple  valve,  either  to  apply 
the  brake  harder  or  release  it. 

The  widespread  use  of  this  system  requires  that  coach 
inspectors  inform  themselves  as  to  its  construction  and 
operation,  and  that  trainmen  and  porters  comply  strictly 
with  the  rules  for  its  operation. 

111.  Q.  Can  you  get  the  emergency  action  of  the 
brake  with  the  pressure  retainer  holding  15  pounds? 

A.  Yes;  if  the  triple  is  in  exhaust  position,  with  brake 
pipe  and  auxiliary  equalized  at  70  pounds,  when  a  sudden 
reduction  of  brake  pipe  pressure  is  made,  it  will  move  the 
triple  piston  full  stroke,  opening  the  emergency  port. 
With  air  at  70  pounds  pressure  in  auxiliary  the  emergency 
piston,  having  only  15  pounds  pressure  under  it,  will  be 
forced  down  at  once,  the  brake  pipe  air  pressure  will  still 
be  so  much  above  15  pounds  that  brake  pipe  air  will  flash 
into  the  brake  cylinder,  and  this  sudden  reduction  made 
by  the  triple  will  affect  the  next  triple  so  it  will  work 
quick-action  also.  Question  50  explains  why  quick-action 
can  not  be  had  after  a  moderate  service  application.  The 
use  of  retainers  interferes  so  little  with  the  quick-action 
that  the  emergency  action  will  jump  over  as  many  cars 
with  the  brakes  cut  out  at  the  cross-over  cocks  with  all 
retainers  holding  15  pounds  as  when  retainers  are  not 
being  used,  provided  the  triple  valve  starts  from  exhaust 
position  and  auxiliary  recharged  to  70  pounds. 


THE   HIGH   SPEED   BRAKE 

For  ordinary  speed,  below  thirty  miles  an  hour,  the  70 
pound  automatic  brake  is  able  to  control  the  train  in  the 
ordinary  manner,  but  when  the  speed  is  much  higher, 
more  power  is  required  in  proportion  as  the  speed  is 
higher.  It  is  the  friction  of  the  brake  shoes  on  the  wheels 
that  arrests  tthe  speed  of  the  train  and  finally  brings  it 
to  a  stop.  In  addition  to  arresting  the  momentum  of  the 
train  this  friction  must  also  arrest  the  rotary  motion  of 
the  wheels  turning  around  at  high  speed;  this  takes  con- 
siderable brake  power.  There  is  a  difference  in  the 
amount  of  the  friction  of  the  same  shoes  and  wheels  at 
different  speeds,  it  being  greater  at  a  low  speed  than  at  a 
high  one. 

What  is  called  the  co-efficient  of  friction,  which  is  the 
proportion  between  the  brake  power  applied  to  the  shoes 
and  their  holding  power,  is  about  .074  at  sixty  miles  an 
hour,  increasing  to  .241  as  the  speed  is  reduced  to  ten 
miles  an  hour,  to  .273  at  five  miles  an  hour  and  just  as  the 
final  stop  is  made  it  is  .330,  so  you  see  the  brake  shoes 
really  hold  less  at  a  high  speed  than  at  a  low  one,  and 
more  brake  power  can  be  applied  at  the  high  speed  than 
could  be  safely  used  at  a  low  one  and  make  the  holding 
power  about  right  for  each  speed. 

Now  it  follows  that  if  the  full  brake  power  was  the 
same  for  all  speeds,  if  it  was  the  proper  power  for  a 
moderate  speed  it  would  be  much  too  low  for  a  high 
speed.  If  a  high  speed  was  the  standard  the  full  brake 
power  would  be  too  high  for  the  low  speed,  the  wheels 
would  skid  on  the  rail  and  a  loss  of  about  two-thirds  of 
the  brake  power  would  result.  This  would  allow  the 
train  to  run  considerable  farther  than  if  the  wheels  were 
held  back  by  the  shoes  just  up  to  the  sliding  point— 
without  sliding. 

Therefore,  an  attachment  to  the  brake  that  would  give 
a  very  high  brake  power  when  first  applied  while  running 
at  a  very  high  speed  and  gradually  reduce  this  brake 


164  THE     HIGH     SPEED    BRAKE 

power  at  about  the  same  rate  the  speed  was  reduced, 
would  be  proper  for  all  speeds. 

This  brake  power  for  moderate  speeds  has  usually 
been  fixed  at  90  per  cent  of  the  weight  of  the  coach 
when  all  the  wheels  have  brake  shoes  applied  ^to  them, 
and  is  about  all  that  can  be  used  without  sliding  the 
wheels  just  as  the  final  stop  is  made. 

This  reduction  of  10  per  cent  from  the  total  load  on 
the  wheels  with  brake  shoes  applied  is  not  exactly  correct 
for  both  light  and  heavy  cars.  If  10  per  cent  of  the 
weight  of  a  car  weighing  50,000  pounds  is  a  proper 
reduction  to  prevent  wheel  sliding,  then  the  same  number 
of  pounds  reduction,  i.  e.,  5,000  pounds  should  be  enough 
for  a  car  weighing  100,000  pounds.  The  old  90  per  cent 
rule  would  give  10,000  pounds  as  the  amount  for  this  car, 
or  5,000  pounds  more  than  needed.  Therefore,  to  get 
the  best  service  the  same  amount  of  reduction  in  pounds 
should  be  made  from  all  cars  braked  to  the  same  per 
cent. 

For  emergency,  the  high  speed  brake  will  apply  the 
brakes  at  first  with  a  brake  power  of  125  per  cent  of  the 
weight  of  the  coach  and  gradually  reduce  the  cylinder 
pressure  aS  the  speed  is  reduced,  till  it  reaches  the 
standard  of  60  pounds,  which  gives  a  90  per  cent  brake 
power,  at  which  point  the  reduction  ceases,  leaving  the 
cylinder  pressure  at  the  amount  and  the  braking  power 
at  the  percentage  at  which  the  wheels  will  not  slide  when 
tHe  car  is  about  to  stop. 

To  £et  this  increased  brake  power  brake  pipe  and 
auxiliary  pressure  is  increased  to  110  pounds.  With  an 
emergency  application  the  pressure  at  first  is  about  85 
pounds.  The  brake  cylinder  pressure  is  reduced  by  an 
automatic  reducing  valve,  which  is  here  illustrated. 

This  reducing  valve,  the  latest  pattern  of  which  is 
shown  in  Fig.  1,  is  fastened  by  the  bracket  at  x  to  the 
coach  frame  (see  Fig.  6)  and  connected  to  the  brake 
cylinder  by  suitable  piping  at  z  (see  Fig.  2).  When  the 
air  enters  the  cylinder  at  the  time  brakes  are  applied,  it 


HIGH  SPEED  BRAKE  AUTOMATIC  REDUCING  VALVE 
FOR  PASSENGER  EQUIPMENT  CARS  AND  LOCOMOTIVES. 
PLATE  F  45.    (1898  Pattern). 


Fifl-6 


166 


OPERATION  OF  REDUCING  VALVE 


also  comes  in  on  top  of  piston  4.  This  piston  is  held  up 
by  the  spring  11  against  a  pressure  of  60  pounds  per  inch, 
if  no  more  than  60  pounds  comes  into  the  cylinder  the 
reducing  valve  remains  stationary  in  the  position  shown 
in  Fig.  3. 

It  should  be  noted  that  the  area  of  the  reducing  valve 
piston  4  that  the  brake  cylinder  air  presses  against  is 
slightly  less  when  the  gasket  20  is  up  solid  to  the  shoulder 
of  the  bushing  e  than  after  it  is  moved  down. 

When  a  graduated  service  application  is  made,  if  the 
brake  cylinder  pressure  raises  above  60  pounds  the  piston 
4  is  moved  down  far  enough  to  open  the  triangular  port 
b  in  the  slide  valve  8  to  exhaust  port  a  in  the  seat  so 
that  the  widest  part  of  port  b  is  open  as  shown  in  Fig.  4. 
Air  can  then  pass,  out  of  brake  cylinder  about  as  fast  as 
it  comes  in  through  graduating  valve  of  the  triple;  when 


Fig  4. 


POSITION  or  POUT*. 
SCMVICC  STOP 

FftCMUNC  CXCCCOINO  «0  POUND* 
.IN  BMAKC  CVtlNDCH. 


brake  cylinder  pressure  drops  below  60  pounds  the  spring 
under  piston  4  moves  slide  valve  8  up  and  laps  ports  a 
and  b}  as  shown  in  Fig.  3,  and  no  more  air  can  escape. 
In  case  an  emergency  application  is  made  the  brake 
cylinder  pressure  rises  like  a  flash  up  to  85  pounds,  piston 


OPERATION  OF  REDUCING  VALVE  167 

4  is  forced  down  at  once  against  the  tension  of  the  spring 
to  the  lower  limit  of  its  travel  into  the  position  shown 
in  Fig.  5.  This  pulls  slide  valve  8  clear  down,  the  small 
end  of  the  triangular  port  b  is  open  to  port  a,  and  brake 
cylinder  air  escapes  slowly  to  atmosphere.  As  pressure 
is  reduced  spring  11  has  power  to  move  piston  4  up  and 
the  triangular  port  b  opens  wider,  which  reduces  the 
brake  cylinder  pressure  faster,  down  to  60  pounds ;  at 
which  point  the  slide  valve  is  moved  up  to  lap  ports  a 
and  b  so  no  more  air  can  escape  from  brake  cylinder ; 
this  position  is  shown  in  Fig.  3. 

The  size  of  this  exhaust  port  b  has  been  determined 
by  experiments  so  as  to  reduce  the  brake  cylinder  pressure 
proportionate  to  the  reduction  in  speed.  It  is  a  different 
size  for  each  size  of  reducing  valve  to  suit  the  different 
volumes  of  air  which  should  pass  out  of  small  and  large 
cylinders  in  about  the  same  time. 

With  a  service  application  the  reducing  valve  reduces 
the  brake  cylinder  pressure  only,  as  the  triple  valve  closes 
the  air  port  from  the  auxiliary.  With  an  emergency 
application  where  the  brake  pipe  pressure  drops  below  60 
pounds  the  triple  holds  the  air  port  open  and  the  reducing 
valve  has  to  reduce  both  brake  cylinder  and  auxiliary 
volumes  to  60  pounds. 

When  the  brake  is  first  set  with  emergency  at  a  high 
speed  the  pressure  is  about  85  pounds  in  the  cylinder; 
as  the  speed  of  the  train  is  reduced  by  the  action  of  the 
brakes,  the  pressure  is  also  reduced  by  the  reducing 
valve  at  about  the  same  rate,  till  it  reaches  60  pounds, 
where  it  remains  till  the  brake  is  released  in  the  regular 
way. 

After  an  emergency  application  the  reducing  valve 
lowers  the  cylinder  pressure  very  slowly  at  first  through 
the  small  pointed  end  of  the  port  b,  and  faster  as  the 
pressure  drops  till  it  reaches  60  pounds,  when  the  valve 
closes.  The  speed  of  the  train  is  reduced  by  the  action 
of  the  brakes  slowly  at  first,  and  the  reduction  of  speed 
is  more  marked  each  succeeding  second  of  time  till  when 


168  OPERATING    THE    HIGH    SPEED   BRAKE 

nearly  at  a  stop  the  speed  is  reduced  very  fast.  The 
pressure  is  reduced  at  about  the  same  ratio  as  the  speed, 
so  as  to  have  it  reach  60  pounds  at  about  the  time  when 
60  pounds  will  do  the  work  properly. 

This  gives  a  very  high  brake  power  ready  to  use  if 
found  necessary  at  high  speeds  and  still  leaves  the  service 
application  feature  unchanged,  ready  for  use  in  ordinary 
stops.  With  the  service  application  the  reducing  valve 
remains  in  position  as  shown  in  Fig.  3.  A  reduction  of 
20  pounds  from  110  applies  the  brake  fully,  as  this 
reduction  will  fill  the  brake  cylinders  at  50  pounds,  the 
full  pressure  of  an  ordinary  service  application;  as  well 
as  leaving  a  high  auxiliary  reservoir  pressure  of  90  pounds 
ready  for  two  more  full  service  applications  of  the  brake 
if  found  necessary  before  re-charging ;  daring  these 
moderate  service  applications  the  reducing  valve  does 
not  move. 

The  brake  pipe  and  auxiliary  pressure  is  set  at  110 
pounds  with  this  type  of  brake — it  may  be  more  if  the  con- 
ditions seem  to  call  for  it.  As  the  engines  equipped  for 
drawing  these  high  speed  braked  trains  may  be  used  to 
draw  coaches  without  the  high  speed  attachments,  some 
arrangement  is  needed  for  changing  the  standard  brake 
pipe  pressure  from  110  pounds  to  the  lower  pressure  and 
vice  versa.  For  this  purpose  there  are  two  feed  valve 
attachments  on  the  engine.  One  of  them,  is  set  at  70 
pounds,  the  other  at  110,  and  there  is  a  reversing  cock 
between  them  which  can  be  turned  to  cut-in  either  one 
for  service  .as  is  desired,  only  one  being  operated  at  a 
time.  This  reversing  cock  and  valves  are  coupled  to  the 
brake  valve  with  suitable  piping.  The  B-6  feed  valve 
can  be  used  instead  of  the  reversing  cock  and  two  feed 
valves.  There  is  a  duplex  governor  for  the  air  pump, 
one  side  of  which  is  set  for  90  pounds  main  reservoir 
pressure,  for  the  ordinary  70  ppunds  brake  pipe  pressure, 
the  other  side  set  at  the  higher  pressure  required,  and  a 
cock  to  cut  out  the  90  pound  side  when  using  the  higher  . 
pressure.  Ten  pounds  excess  has  been  found  sufficient 


OPERATING    THE    HIGH    SPEED   BRAKE  J.69 

with  a  short  train,  but  more  is  needed  with  a  longer 
train;  in  some  cases  30  pounds,  in  order  to  be  sure  to 
release  all  brakes,  after  a  light  application.  The  tender 
is  equipped  with  a  quick-action  triple  and  reducing  valve 
the  same  as  a  coach.  An  engine  truck  brake  is  a  neces- 
sary part  of  this  equipment,  which  is  supplied  with  air 
from  the  driver  brake  triple;  a  reducing  valve  similar  to 
the  coaches  is  used,  set  at  50  pounds.  Any  extra  coaches 
placed  on  these  high  speed  braked  trains  require  a  reduc- 
ing valve,  although  a  safety  valve  set  to  blow  off  at  60 
pounds  through  a  restricted  opening  can  be  used  tem- 
porarily by  screwing  it  into  the  oiling  plug  hole  in  the 
cylinder  head.  This  safety  valve  is  not  as  reliable  as 
the  reducing  valve,  and  is  only  used  as  a  temporary 
relief. 

This  type  of  brake  will  stop  a  train  running  at  sixty 
miles  per  hour  in  about  450  feet,  less  distance  than  the 
ordinary  quick-action  brake  with  70  pounds. 

In  making  a  graduated  service  application,  with  a 
pressure  of  60  pounds  in  the  brake  cylinder,  when  a 
further  service  reduction  of  brake  pipe  pressure  is  made, 
the  cylinder  pressure  will  increase  but  slightly  above  60 
pounds  and  immediately  be  reduced  to  that  amount  unless 
a  full  continuous  service  reduction  is  made,  in  which 
case  the  pressure  may  rise  to  77  or  80  pounds,  being 
soon  reduced  to  60  pounds  by  the  reducing  valve.  After 
a  cylinder  pressure  of  60  pounds  is  obtained,  a  .full 
service  reduction  to  below  60  pounds  should  never  be 
made,  except  at  high  speeds  in  an  emergency. 

A  high  speed  brake  train  is  handled  in  the  same 
manner  an  expert  engineer  handles  an  ordinary  passenger 
train  of  the  same  length.  Remember  that  air  at  110 
pounds  pressure  moves  through  the  air  ports  more  rapidly 
than  at  70  pounds,  so  when  listening  to  the  sound  of  the 
air  discharging  from  the  preliminary  and  brake  pipe 
exhausts  watch  the  gage  closely.  To  make  the  brake 
valve  reduction  more  gradual  a  larger  brake  valve  reser- 


170  HIGH    SPEED    BRAKE    PRESSURES 

voir    is   now    used,    which    holds    about    812    cubic    inches. 
The  older  ones  hold  close  to  600  cubic   inches. 

A  20  pound  service  reduction  will  give  about  the  same 
brake  cylinder  pressure  from  110  pounds  that  it  does 
from  70,  i.  e.,  about  50  pounds. 

A  22  pound  service  reduction  will  give  close  to  60 
pounds  in  the  cylinder,  anything  over  that  may  be  wasted, 
as  the  reducing  valves  will  not  let  the  cylinder  pressure 
rise  above  60  pounds. 

With  110  pounds  on  the  back  of  the  slide  valve  at  the 
beginning  of  a  service  application  and  90  pounds  at  the 
time  of  a  release,  the  slide  valve  cannot  be  moved  as 
easily  by  the  triple  piston  as  when  the  pressures  are  70 
and  50  pounds,  and  it  will  take  more  change  of  pressures 
each  side  of  the  triple  piston  to  move  it. 

Triple  valves,  when  dirty,  or  when  they  need  oiling, 
give  more  trouble  with  110  pounds  than  with  70,  on 
account  of  the  increased  pressure  on  the  slide  valve  which 
makes  them  more  apt  to  work  quick-action  with  a  gradual 
service  reduction.  For  that  reason  both  the  triple  valves 
and  brake  valve  must  be  kept  clean  and  well  oiled  and 
good  stiff  excess  is  needed  with  a  long  train. 

When  coupling  to  a  train  having  110  pounds  brake  pipe 
pressure  with  an  engine  carrying  70  and  90  pounds,  put 
the  brake  valve  on  lap  and  leave  it  there  till  the  110 
pounds  pressure  has  blown  down  to  70  pounds  and  the 
reducing  valves  on  the  cars  have  blown  down  to  60 
pounds.  Then  with  full  excess  go  to  full  release  and 
the  brakes  should  all  release.  With  L  triples  it  is  neces- 
sary to  carry  the  high  pressure  on  the  engine  to  release 
the  brakes. 

In  handling  any  very  long  passenger  train  a  straight 
air  brake  on  the  engine  and  tender  is  a  valuable  aid  in 
preventing  break-in-twos  or  serious  shocks  when  releasing 
at  a  slow  speed,  the  ET  equipment  on  the  locomotive  is 
still  better. 

f  Unless   an    emergency   arises   requiring   a   very   sudden 
stop,    do    not    use    the    emergency    application    with    110 


USE    OF    EMERGENCY  171 

pounds,  when  running  at  a  slow  speed,  say  below  twenty- 
five  miles  an  hour.  Unless  the  rail  conditions  are  perfect 
the  wheels  are  apt  to  slide ;  this  will  increase  the  length 
of  the  stop.  When  an  emergency,  such  as  danger  to  life 
or  property,  confronts  you,  remember  that  all  the  brakes 
act  quickly  with  the  emergency  application — in  less  than 
three  seconds — which  they  will  not  do  as  quickly  with  a 
service  application.  Difference  in  piston  travel  does. not 
affect  the  work  of  the  high  speed  brake  as  much  as  it 
does  the  70  pound  brake  with  full  service  applications. 
As  soon  as  the  reducing  valve  operates  it  equalizes  the 
cylinder  pressures  for  long  and  short  travels,  for  all  will 
reduce  to  the  same  final  pressures.  If  the  leverage  is 
proper,  all  cars  will  be  braking  alike.  One  of  the  best 
preventives  of  wheel  sliding  is  equal  and  maximum  brake 
power  on  all  the.  cars,  tender  and  engine.  With  all  wheels 
holding  back  alike  tests  show  that  wheel  sliding  is  rare. 


PLATE  F.48 


HIGH   PRESSURE   CONTROL 

With  the  heavy  capacity  cars  now  in  general  use,  the 
empty  weight  of  the  car  on  which  the  braking  power  is 
calculated  is  such  a  small  proportion  of  the  full  loaded 
weight  that  some  provision  must  be  made  to  increase  the 
braking  power  on  the  loaded  cars.  This  is  particularly 
the  case  with  coal  and  ore  cars,  which  usually  run  empty 
to  the  mines  -and  return  loaded.  For  this  class  of  cars  a 
two-pressure  system  has  been  devised  in  which  a  moder- 
ately low  pressure  of  55  to  65  pounds  is  carried  in  the 
brake  pipe  and  auxiliaries  of  the  empties, 
while  with  the  loaded  trains  90  pounds 
can  be  carried  and  thus  increase  the  brake 
power  about  50  per  cent.  The  duplex 
governor  and  reversing  cock  which  is  part 
of  the  High  Speed  Brake  is  used  with  the 
High  Pressure  Control,  but  the  duplex 
governor  is  piped  a  little  different.  There 
are  two  separate  pipes  leading  to  the  gov- 
ernor,, one  from  the  main  reservoir  to  the 
side  of  the  governor  set  for  the  highest 
pressure,  the  other  pipe  leading  from  the 
left  side  of  the  reversing  cock,  which  is 
set  for  the  lowest  pressure,  to  the  low 
pressure  side  of  the  governor,  so  that  when 
the  low  pressure  feed  valve  is  cut  in,  the  low  pressure 
governor  is  also  cut  in. 

When  handling  a  train  of  empties  going  up  hill  the 
low  pressure  is  used,  coming  down  hill  with  a  train  of 
loads  the  high  pressure  is  used,  and  thus  the  train  can  be 
controlled.  Any  empty  cars  in  the  train  must  have  the 
air  brake  cut  out  at  cross-over  pipe  when  using  the  high 
pressure  to  avoid  sliding  wheels;  unless  the  caboose  has 
a  safety  valve,  it  must  be  cut  out  also. 

A  safety  valve  shown  on  this  page  is  attached  to  the 
brake  cylinders  of  the  engine  and  tender.  This  same  type 
of  valve  is  also  used  on  any  extra  coaches  set  in  a  High 
Speed  -Brake  train. 


SAFETY  VALVE. 


THE    AMERICAN     AUTOMATIC     SLACK     ADJUSTER  173 


THE  AMERICAN  AUTOMATIC  SLACK  ADJUSTER 

The  illustrations  of  the  American  Brake  Ox's"  Auto- 
matic Slack  Adjuster  show  how  the  adjuster  cylinder 
and  adjusting  screw  is  attached  to  the  brake  cylinder  and 
dead  cylinder  lever.  A  small  port  is  drilled  and  tapped 
in  the  brake  cylinder  at  the  point  a,  which  is  to  be  the 
limit  of  the  running  piston  travel.  A  pipe  E  is  connected 
from  this  port  a  to  the  adjuster  cylinder  at  G. 

The  brake  piston  acts  as  a  valve  to  admit  air  to  the 
adjuster  cylinder.  When  it  moves  beyond  port  a  during  a 
brake  application,  air  from  behind  brake  piston  passes 
out  of  port  a  through  pipe  E  into  the  slack  adjuster 
cylinder,  pushes  the  piston  to  the  left  against  the  strength 
of  the  coiled  spring,  carrying  the  pawl  out;  the  flat  spring 
pushes  the  pawl  down,  hooking  it  down  over  a  tooth  of 
the  ratchet  nut.  When  the  brake  is  released,  air  in  the 
adjuster  cylinder  passes  out,  spring  then  returns  the 
adjuster  piston  to  its  normal  position  which  pulls  back 
pawl;  this  rotates  ratchet  nut  on  the  screw  attached  to 
the  dead  cylinder  lever  fulcrum  jaw,  moving  the  end  of 
the  lever  up  1/32  of  an  inch,  taking  up  some  slack  in  the 
brake  rigging.  The  slack  is  not  taken  up  when  the  brake 
is  applied,  but  after  it  is  released,  when  there  is  no  strain 
on  the  cylinder  lever.  When  the  coiled  spring  pushes 
back  the  piston  and  pulls  the  pawl,  the  lug  strikes  the 
stop,  this  raises  the  pawl  out  of  the  ratchet,  so  that  the 
ratchet  nut  can  be  turned  either  way,  if  the  adjuster 
piston  is  in  normal  position,  this  will  allow  nut  to  be 
turned  by  hand  to  let  out  or  take  up  slack  in  brake  rig- 


OPERATING    THE    SLACK    ADJUSTER  175 

ging  when  new  shoes  are  put  on,  or  repairs  made  to  brake 
gear.  In  case  the  ratchet  nut  is  turned  on  its  screw  till 
the  jaw  is  pulled  up  solid  against  the  adjuster  cylinder, 
in  the  older  type,  the  pawl  cannot  be  moved  far  enough 
by  the  spring  to  have  the  lug  strike  the  stop;  in  which 
event  the  casing  must  be  opened  up  and  the  pawl  raised 
out  of  the  ratchet  nut,  so  it  can  be  turned  by  hand.  A 
later  type  of  American  Adjuster  has  a  stop  screw  located 
near  the  adjuster  cylinder,  so  arranged  that  the  jaw  comes 
in  contact  with  it  instead  of  the  cylinder;  by  removing 
this  screw  and  turning  the  ratchet  by  hand  the  pawl  is 
released.  A  still  later  type  has  a  tap  bolt  in  the  end  of 
the  the  adjuster  nut  casing,  slack  off  this  tap  bolt  and  the 
screw  will  turn  a  little  more  and  release  the  pawl.  The 
pawl  and  ratchet  are  enclosed  in  a  tight  case  to  keep  out 
ice  and  foreign  matter  which  would  prevent  their 
movement. 

In  case  the  brake  piston  does  not  travel  to  port  a  the 
adjuster  does  not  move  any  of  its  parts,  but  is  at  rest.  If 
port  a  is  partially  or  fully  opened  by  the  piston,  which 
acts  as  a  valve,  compressed  air  is  admitted  to  the  adjuster 
cylinder,  so  it  is  operated. 

Slack  adjusters  take  up  the  travel  beyond  a  certain 
running  travel  limit.  The  brake  piston  will  travel  farther 
on  a  running  car  than  one  standing  still,  because  the 
journals  and  bearings  will  be  crowded  to  one  side  of  the 
oil  boxes  and  all  lost  motion  that  can  be  taken  up  in  the 
truck  comes  out  when  running.  For  that  reason  the 
piston  travel  is  usually  found  to  be  less  when  measured 
at  a  standing  test  than  the  actual  distance  of  the  port  a 
from  the  pressure  head  of  the  cylinder.  If  this  port  a 
is  eight  inches  from  the  head  to  allow  eight  inches  travel 
it  is  not  unusual  to  find  the  travel  at  a  standing  test,  less 
than  six  inches.  When  locating  port  a  first  see  how  far 
the  edge  of  the  piston  packing  leather  is  from  pressure 
head  x.  Port  a  is  very  small  where  it  comes  through  the 
wall  of  the  cylinder,  so  that  the  piston  packing  leather 
will  not  be  quit  when  passing  over  the  opening. 


176  TAKING     UP     THE     SLACK 

The  amount  of  slack  depends  on  the  brake  leverage. 
For  instance,  a  10-inch  brake  cylinder  has  a  power  of 
4,700  pounds.  If  it  is  used  on  a  coach  weighing  52,220 
pounds,  90  per  cent  of  this  weight  is  47,000  pounds,  so 
the  brake  power  required  at  the  shoes  is  ten  times  that  at 
the  piston,  or  a  total  leverage  of  10  to  1.  With  a  car 
weighing  36,550  pounds  the  brake  power  would  be  32,900 
or  a  total  leverage  of  7  to  1.  Now  with  the  same  amount 
of  slack  on  the  shoes  of  each  car  one  car  would  have  10 
inches  piston  travel,  the  other  would  have  only  7  inches. 
With  a  leverage  of  over  10  to  1  you  cannot  restrict  the 
piston  travel  to  6  inches  and  have  the  shoes  clear  the 
wheels  so  the  coach  will  pull  easy  between  the  stations. 

One  of  the  errors  made  when  taking  up  slack  by  hand 
is  using  shoe  clearance  instead  of  piston  travel  as  a  guide. 
With  a  light  car  and  large  cylinder,  where  the  total 
leverage  is  low,  there  will  be  considerable  clearance  in 
proportion  to  the  piston  travel.  If  the  slack  is  taken 
up  the  same  as  for  a  car  of  heavy  leverage,  the  brake 
piston  will  not  pass  over  the  leakage  groove  with  mod- 
erate service  applications.  On  the  other  hand,  with  a 
heavy  car,  the  piston  may  bottom  on  the  cylinder  head. 
For  this  reason  a  device  that  will  regulate  the  piston 
travel  while  the  train  is  under  way  will  do  better  work 
than  hand  regulation. 

Uniform  piston  travel  is  one  of  the  prerequisites  of 
good  brake  service.  When  this  can  be  automatically  main- 
tained during  an  entire  trip  it  ensures  a  uniform  as  well 
as  a  maximum  efficiency  of  the  brakes.  If  this  adjustment 
is  made  by  hand  the  piston  travel  varies  considerable  on 
a  long  trip  with  a  corresponding  loss  of  efficiency. 

Unequal  piston  travel  is  the  cause  of  a  good  many 
slid  flat  wheels  in  coach  equipment,  and  is  responsible  for 
most  of  the  break-in-twos  in  long  freight  trains.  The 
braking  power  is  increased  by  short  travel  and  reduced 
by  long  travel,  so  that  a  coach  with  short  travel  may 
have  power  enough  to  slide  the  wheels  when  the  other 
cars  do  not  skid. 


BRAKE   LEVERAGE 

Ability  to  figure  up  brake  leverage  is  an  accomplish- 
ment for  an  air  brake  operator — not  always  a  necessity — 
it  pays  to  know  something  definite  about  it.  The  rules 
are  not  complicated  and  formulas  help  to  shorten  the 
calculations.  You  should  first  learn  how  the  several 
classes  of  levers  operate  and  the  difference  between  those 
of  the  first,  second  and  third  kind.  A  lever  of  the  first 
kind  has  the  power  applied  at  one  end,  the  weight  to  be 
moved  is  at  the  other  end  and  the  fulcrum  which  takes 
both  the  strain  of  the  power  and  the  resistance  of  the 
weight  is  in  between  the  ends;  in  the  cut  of  a  lever  of 
the  first  kind  F  is  the  force  or  power  coming  from  the 
top  rod,  C  in  the  middle  is  the  fulcrum  and  W  at  the 
bottom  is  the  brake  beam  or  weight  to  be  moved.  The 
cylinder  lever  connected  to  the  brake  piston  is  of  the  first 
Idnd.  A  pinch  bar  when  we  pry  down  on  the  rail  and 
against  the  tire  of  a  driving  wheel  is  a  good  illustration 
of  this  class  of  lever. 

A  lever  of  the  second  kind  has  the  power  F  applied  at 
one  end,  the  fulcrum  C  is  at  the  other  and  the  weight  or 
brake  beam  to  be  moved  is  between  them  at  W;  the  live 
lever  of  an  outside  hung  brake  is  usually  of  the  second 
kind.  If  you  use  the  pinch  bar  by  passing  it  under  the 
object  to  be  moved,  resting  one  end  on  the  ground  and 
lifting  up  on  the  other  it  will  show  you  the  second  kind. 

With  a  lever  of  the  second  kind  the  weight  W  takes 
as  much  strain  as  both  the  power  F  and  fulcrum  C.  A 
lever  of  the  third  kind  has  the  power  F  attached  between 
the  ends  W  and  C ;  a  lever  of  this  class  takes  more  power 
in  proportion  to  the  weight  to  be  moved  than  either  of  the 
other  kinds.  With  any  class  of  lever  the  strains  at  the 
ends  added  together  equal  the  strain  in  the  middle.  So 
you  see  the  power  developed  by  any  one  of  three  kinds  of 
levers  of  the  same  length  depends  on  the  relative  positions 
of  the  power,  weight  and  fulcrum. 

When    you    make    measurements    and    calculations    of 


CALCULATING    BRAKE    LEVERAGE 


179 


brake  power,  in  case  the  pins  or  brake  jaws  are  much 
worn  set  the  brake  by  hand  and  measure  the  levers 
carefully  as  a  mistake  of  a  very  short  distance  on  the 
short  end  of  a  live  lever  will  alter  the  power  considerable. 
Always  multiply  the  power  or  force  in  pounds  by  the 
distance  in  inches  from  the  point  F  where  power  is 
attached  to  the  fulcrum  C,  and  divide  this  product  by  the 
distance  in  inches  from  fulcrum  C  to  brake  beam  W. 


1-EVER  or  2ND  KIND        LEVER  or  3m»  KINO 


On  page  177  is  a  small  cut  of  the  arrangement  of 
levers  for  a  coach  brake  with  Hodge  system  which  we 
will  use  to  illustrate  this  explanation. 

Beginning  at  the  brake  cylinder  where  the  power  is 
first  exerted,  the  pressure  at  F  where  the  piston  is 
attached  to  live  cylinder  lever  is  4,700  pounds  for  a  10-inch 
cylinder  with  quick-action  triple.  This  lever  being  of  the 
first  kind  with  fulcrum  C  between  the  ends,  we  multiply 
the  power  4,700  by  12,  the  distance  to  the  fulcrum  C,  and 


180  CALCULATING    BRAKE    LEVERAGE 

divide  this  product  by  115^,  the  distance  from  the  fulcrum 
to  W,  the  Hodge  lever  rod  connection,  and  have  4,900' 
pounds  strain  on  this  rod  which  goes  to  the  Hodge  lever 
at  X.  This  is  a  lever  of  the  third  class  and  being  equally 
divided,  each  end  gets  half  this  power  or  2,450  pounds, 
which  is  the  force  at  the  top  end  of  the  live  truck  lever. 
We  next  multiply  2,450  by  the  distance  on  this  lever  from 
F  to  C,  36  inches,  and  divide  this  product  by  8,  the  distance 
from  C  to  W,  and  we  have  11,000  pounds,  the  strain  on 
the  brake  beam.  A  shorter  way  is  to  multiply  the  pull 
at  top  end  of  live  lever  2,450  pounds,  by  4}/2,  the  propor- 
tion of  the  live  lever.  To  get  the  proportions  of  a  live 
lever,  divide  the  total  length  between  the  centers  of  out- 
side pin  holes  at  F  and  C  by  the  distance  from  C  to  W — 
called  the  short  end — in  this  case  8  into  36  or  4^2  to  1. 
If  the  force  at  F  is  2,450  pounds  and  the  strain  at  W  is 
11,000  pounds,  the  resistance  at  C  will  be  8,550  pounds, 
as  the  sum  of  the  strains  at  both  ends  of  a  lever  must 
balance  the  strain  in  the  middle.  This  strain  of  8,550 
pounds  on  the  bottom  rod  goes  to  the  bottom  end  of 
the  dead  truck  lever  at  F  and  is  to  be  multiplied  by  the 
distance  from  F  to  C — the  outside  length  of  dead  lever — 
and  the  product  divided  by  the  distance  from  C  at  the  top 
end  of  dead  lever  to  W  the  brake  beam  connection;  if  the 
dead  lever  is  the  same  proportion  as  the  live  one  the 
result  will  be  11,000  pounds. 

Now  going  back  to  the  cylinder  levers,  the  tie  rod  has 
a  strain  of  9,600  pounds  which  is  the  sum  of  4,700  and 
4,900,  the  strains  on  both  ends  of  the  live  cylinder  lever. 
This  strain  goes  to  the  point  F  in  the  floating  cylinder 
lever  which  is  shown  fulcrumed  at  C  on  the  cylinder  head 
and  its  free  end  W  connected  to  the  Hodge  rod  for  the 
floating  lever  at  the  other  end  of  the  car  and  from  there 
the  power  goes  to  the  live  and  dead  truck  levers  of  the 
other  truck  as  already  explained. 

By  this  arrangement  of  levers  we  get  a  braking  power 
on  each  end  of  the  car  equal  on  both  trucks,  with  a  total 
amounting  to  twice  what  the  brake  piston  has ;  but  we  get 


CALCULATING     BRAKE     POWER  181 

it  because  the  piston  travels  twice  as  far  as  it  would  if  the 
fulcrum  C  in  the  live  cylinder  lever  was  fixed  stationary; 
both  cylinder  levers  move  and  the  piston  travels  far 
enough  for  the  two. 

Both  cylinder  levers  need  not  be  of  the  same  length, 
but  they  must  be  of  the  same  proportion  if  the  same  strain 
is  to  go  to  each  end  of  the  car.  Coaches  have  cylinder 
levers  exactly  alike  for  each  end  of  the  coach ;  freight  cars 
do  not,  although  they  are  the  same  proportion. 

In  making  calculations  for  braking  power  for  coach 
equipment,  take  90  per  cent  of  the  weight  which  the 
wheels  having  brake  shoes  attached  put  on  the  rail  under 
them.  With  all  wheels  braked  this  means  90  per  cent  of 
the  weight  of  the  coach  when  empty,  a  twelve  wheel 
coach  with  only  eight  wheels  braked  takes  8/12  of  the 
weight  as  a  basis  for  calculation.  Use  70  per  cent  of 
the  light  weight  of  any  freight  car  used  in  interchange 
service;  while  100  per  cent  of  the  light  weight  of  a 
tender  is  generally  used,  a  tender  usually  has  a  supply 
of  water,  fuel  and  tools  which  hold  its  weight  up  above 
the  skidding  point.  The  light  weight  of  cars  and  coaches 
is  used  when  making  leverage  calculations  1p  keep  the 
brake  power  below  the  limit  at  which  the  wheels  will 
slide  when  the  brake  is  operated  on  an  empty  car.  If  the 
brake  cylinder  receives  its  supply  of  air  from  the  auxiliary 
only,  as  is  the  case  with  the  plain  triple  valve  and  some 
of  makes  of  quick-action  triples,  use  50  pounds  as  the 
equalized  piston  and  auxiliary  pressure.  If  part  of  the 
supply  comes  from  the  brake  pipe,  as  is  the  case  with 
the  Westinghouse  quick-action  triple,  use  60  pounds. 

Driver  brake  leverage  is  75  per  cent  of  the  weight  at 
the  rail;  an  engine  truck  brake  should  have  less  than  that, 
as  there  is  no  way  to  get  sand  to  the  rails  for  the  truck 
wheels  on  slippery  track. 


CAM    DRIVER   BRAKE   LEVERAGE 

The  limited  space  in  this  book  will  not  allow  a  full 
description  of  how  the  cams  and  levers  are  designed,  but 
some  information  on  calculating  their  brake  power  will 
come  handy  to  the  men  operating  them.  The  illustration 
of  the  cam  brake  shows  its  various  parts. 


CflMSCftZW  PI 


FORMULR. 


These  cams  are  really  segments  of  wheels  with  x-x  for 
the  centers.  If  they  are  properly  laid  out  no  matter  how 
far  they  roll  down,  the  point  of  contact  at  the  edges  of  the 
wheels  will  always  be  on  the  line  between  the  centers  x-x. 

The  cam  as  used  with  the  brake  is  a  bell  crank  with 
the  long  arm  from  g  to  x  and  the  short  arm  from  x  to  a. 
A  true  bell  crank  requires  a  fixed  fulcrum  at  x  to  act  as  a 
brace  to  transmit  the  power  at  g  to  a,  but  in  the  case  of 
the  cams  no  fulcrum  is  needed  there,  for  the  faces  of  the 
cams  rolling  against  each  other  act  as  fulcrums. 


CAM     DRIVER     BRAKE     LEVERAGE  183 

To  calculate  the  brake  power,  set  the  brake  full  on  and 
measure  the  distance  between  the  cam  link  pins  at  a-a. 
Also  measure  the  distance  between  the  cam  link  pins  g-g 
and  subtract  this  distance  from  the  distance  a-a;  one-half 
of  this  remainder  will  be  the  long  arm  of  the  bell  crank 
included  in  the  design  of  each  cam,  which  distance  we  will 
call  X  in  the  formula.  We  do  not  measure  clear  to  the 
face  of  the  cam,  because  the  power  is  applied  at  g-g, 
one-half  of  the  power  exerted  by  the  piston  going  to 
each  cam. 

As  the  cams  roll  down  against  each  other  when  the 
brake  is  set  their  faces  touch  at  one  point  only,  which  we 
will  call  the  point  of  "rolling  contact."  Place  a  straight 
edge  from  one  of  the  cam  screw  pins  at  a  to  the  other, 
on  a  line  with  their  centers  and  measure  from  the  straight 
edge  up  to  the  point  of  rolling  contact;  this  distance  is  the 
other  arm  of  the  bell  crank,  it  is  called  the  "offset,"  and 
is  the  distance  from  a  to  x  also ;  this  is  named  O  in  the. 
formula.  This  last  distance  divided  into  the  length  of  the 
line  from  b  to  a — the  long  arm  of  the  bell  crank — gives 
the  leverage  of  the  cam. 

Multiply  this  leverage  by  1,250  for  an  8-inch  cylinder 
or  by  2,000  for  a  10-inch  cylinder,  which  will  give  the 
power  delivered  at  the  bottom  end  of  the  lever  at  a. 
Multiply  this  power  by  the  whole  length  of  the  lever  from 
a  to  k,  called  Z  in  the  formula,  and  divide  the  product  by 
the  distance  from  the  pin  k  to  the  pin  i  the  brake  shoe 
head,  which  is  distance  Y ;  this  quotient  is  the  brake  power 
delivered  at  that  shoe;  four  times  the  power  for  one  shoe 
will  be  the  brake  power  for  all  shoes,  which  should  be  75 
per  cent  of  the  weight  on  drivers.  In  all  these  calcula- 
tions we  use  50  pounds  as  the  air  pressure  per  inch  on 
the  brake  piston. 

To  calculate  the  other  way,  take  75  per  cent  of  the 
weight  on  the  rail  at  the  drivers,  one-fourth  of  that  will 
be  the  power  required  at  each  shoe.  Multiply  this  amount 
by  the  length  in  inches  of  the  lever  from  i  to  k  and  divide 


184  CAM     DRIVER    BRAKE    LEVERAGE 

the  product  by  the  length  from  k  to  a;  this  last  amount 
will  be  the  power  required  at  a,  delivered  by  the  cam. 

Divide  this  by  1,250  for  an  8-inch  cylinder  or  by  2,000 
for  a  10-inch  cylinder,  the  quotient  will  be  the  "leverage" 
of  the  cam,  and  should  correspond  exactly  with  the  cam  in 
use.  To  get  the  leverage  of  the  cam,  divide  the  length  at 
X  by  the  offset. 

The  cams  are  designed  to  give  the  full  brake  power  of 
75  per  cent  of  the  weight  on  drivers  when  the  shoes  and 
tire  are  worn  down  to  their  limit.  The  brake  power 
increases  as  the  length  of  the  cam  X  is  increased  by  wear 
of  shoes  and  tires,  but  this  does  not  affect  the  "offset"  O. 
Therefore,  with  thick  new  tire  and  new  shoes  you  will  not 
get  the  full  brake  power,  because  the  long  lever  of  the  bell 
crank  in  the  cam  is  not  the  full  length  as  laid  out  for  a 
thin  tire.  To  avoid  the  difficulty  of  having  too  much 
leverage  with  thin  tire  the  radius  of  the  face  of  the  cam 
is  struck  from  a  point  one  and  one-fourth  inches  further 
out  than  at  x.  A  thick  or  thin  shoe  does  not  change  the 
power  as  much  where  the  cams  are  long  with  long  wheel 
base  as  with  very  short  cams. 

If  you  find  that  with  a  short  piston  travel,  say  two 
inches,  the  cams  do  not  roll  down  so  that  their  faces 
separate  at  the  lower  corners,  as  shown  in  the  illustration, 
the  cam  links  are  too  short.  It  is  not  unusual  to  find 
these  links  put  up  too  short,  and  this  defect  reduces  the 
brake  power  very  materially.  Changing  the  brake  heads 
and  putting  on  a  wide  one  in  the  place  of  a  narrow  head 
also  reduces  the  brake  power,  as  it  shortens  the  length  of 
the  cam.  A  thick  shoe  reduces  the  power  the  same  way. 

In  any  brake  the  proportion  between  the  piston  travel 
and  the  brake  shoe  travel  is  the  leverage.  For  instance,  if 
the  piston  travel  is  four  inches  and  the  brake  shoes  travel 
one-half  inch,  the  proportion  is  eight  to  one,  so  the  power 
from  the  piston  is  multiplied  eight  times.  If  you  can  get 
the  exact  brake  shoe  travel  of  a  brake  and  divide  it  into 
the  piston  travel  you  can  easily  find  the  brake  power. 


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CALCULATIONS  FOR  AIR  PRESSURES 

To  calculate  at  what  finail  pressure  two  separate 
volumes  of  air  at  different  pressures  will  equalize  when 
connected  so  air  will  flow  from  the  higher  to  the  lower 
pressure,  it  is  necessary  to  reduce  the  volumes  and  press- 
ures to  one  standard  of  comparison. 

Suppose  that  a  reservoir  has  a  volume  of  1,620  cubic 
inches  with  a  gage  pressure  of  70  pounds  per  inch.  If 
that  same  air  was  expanded  to  one  pound  gage  pressure 
per  inch  it  would  occupy  seventy  times  as  much  space  or 
70x1,620,  which  is  113,400  cubic  inches  at  one  pound  press- 
ure. We  will  call  this  amount  cubic-inch-pounds,  all 
volumes  and  pressures  can  be  reduced  to  this  standard. 

A  gage  shows  the  pressure  above  the  atmospheric 
line,  but  absolute  pressure  begins  at  the  vacuum  line ;  to 
get  absolute  pressure  we  add  fifteen  pounds  to  the  press- 
ure shown  on  the  gage,  before  the  calculations  are  made 
and  subtract  fifteen  pounds  from  the  result  to  get  back 
to  the  gage  pressure  again.  If  the  calculations  refer  to 
volumes  which  contain  air  at  or  above  the  atmospheric 
pressure,  this  fifteen  pounds  need  not  be  taken  into 
account.  If  any  question  of  piston  travel  is  connected  with 
it,  the  fifteen  pounds  must  be  considered. 

We  will  take  the  case  of  a  main  reservoir  of  16,000 
cubic  inches  at  90  pounds,  and  an  empty  brake  pipe  of 
twenty-five  cars  which  have  the  same  volume.  Multiply 
main  reservoir  volume  by  its  pressure  and  divide  the 
product  by  the  combined  volume  of  both  reservoir  and 
brake  pipe.  16,000x90—1,440,000  cubic-inch-pounds,  this 
divided  by  32,000  gives  45,  the  gage  pressure  at  equaliza- 
tion. 

Suppose  this  brake  pipe  instead  of  being  empty  has  40 
pounds  gage  pressure  in  it,  and  the  main  reservoir  90; 
40  pounds  in  the  brake  pipe  will  be  640,000  cubic-inch- 
pounds,  this  added  to  the  amount  in  the  reservoir  and 
the  sum  divided  by  the  combined  volumes  will  give  sixty- 
five  as  the  pressure  at  equalization. 


CALCULATIONS    FOR    AIR    PRESSURES  187 

A  retaining  valve  is.  holding  15  pounds  in  the  brake 
cylinder.  After  charging  the  auxiliary  to  70  another  full 
application  is  made,  we  can  figure  the  equalizing  pressure 
as  follows  :  450  cubic  inches  at  15  pounds  is  6,750  cubic- 
inch-pounds.  The  auxiliary  at  70  holds  113,400  cubic- 
inch-pounds,  the  total  amount  in  both  is  120,150  cubic- 
inch-pounds,  which  now  expands  into  the  total  volume  of 
1,620  plus  450  or  2,070  cubic  inches.  Divide  the  full 
amount  of  air  by  the  total  space  and  we  have  58  pounds, 
We  do  not  figure  from  the  vacuum  line  in  this  case. 

When  calculating  the  pressure  at  which  the  brake 
cylinder  and  auxiliary  will  equalize  when  the  piston  moves 
out,  remember  that  there  is  no  atmospheric  air  in  the 
space  left  by  the  piston  in  moving  out  and  this  space  must 
be  filled  with  air  from  the  vacuum  line  of  absolute  press- 
ure, so  we  must,  add  15  pounds  to  the  gage  pressure  of 
70  pounds,  which  gives  85  pounds. 

The  auxiliary  holds  about  1,620  cubic  inches  at  85 
pounds,  this  is  137,700  cubic-inch-pounds  absolute  pressure. 
The  volume  of  an  8-inch  brake  cylinder  with  8  inches 
travel,  including  clearance  and  piping  from  the  triple,  is 
close  to  450  cubic  inches;  the  combined  volume  is  2,070 
cubic  inches.  Divide  137,700  by  this  combined  volume 
and  subtract  fifteen  from  the  quotient,  you  will  then  have 
the  equalizing  pressure,  about  51.5  pounds. 

To  find  how  much  brake  cylinder  air  at  60  pounds 
comes  from  the  brake  pipe  with  an  emergency  application 
and  how  much  from  the  auxiliary,  proceed  as  follows: 
The  brake  cylinder  volume  of  450  cubic  inches  at  75 
pounds  absolute  pressure  is  33,750  cubic-inch-pounds.  The 
auxiliary  of  1,620  cubic  inches  loses  10  pounds,  from 
70  down  to  60;  this  is  16,200  cubic-inch-pounds  from  the 
auxiliary;  this  subtracted  from  33,750  leaves  17,550  cubic 
pounds  to  come  from  the  brake  pipe.  Divide  17,550  by  the 
volume  450  cubic  inches  we  have  39  pounds  absolute  press- 
ure; subtracting  15  pounds  to  get  gage  pressure  we  have 
24  pounds  as  the  part  the  brake  pipe  supplies;  this  varies 


188  PRESSURE    WITH    PARTIAL    APPLICATION 

with  the  piston  travel  and  condition  of  strainers,  it  is 
usually  less  than  this. 

When  you  make  a  partial  application  of  the  brake  and 
want  to  know  what  brake  cylinder  pressure  will  result 
from  any  certain  reduction  in  the  auxiliary,  proceed  as 
follows :  Say  we  make  a  10  pound  reduction.  If  the 
volume  of  the  auxiliary  is  1,620  cubic  inches,  at  10  pounds 
per  inch  the  total  amount  passing  from  the  auxiliary  to 
the  brake  cylinder  would  be  16,200  cubic-inch-pounds.  In 
this  calculation  we  will  allow  for  the  air  contained  in  the 
clearance  space  of  the  cylinder,  the  auxiliary  tube  between 
the  triple  valve  and  cylinder,  and  the  triple  valve  itself, 
which  amounts  to  an  average  of  47.92  cubic  inches,  which 
contains  air  at  15  pounds  per  inch  or  close  to  718  cubic- 
inch-pounds.  This  added  to  the  amount  coming  in  frohi 
the  auxiliary  makes  16,918  cubic-inch-pounds,  and  it  will 
equalize  in  the  450  cubic  inches  'total  volume  of  the  brake 
cylinder  and  clearance  at  38  pounds  absolute  pressure,  or 
23  pounds  gage  pressure.  You  can  calculate  for  any  given 
reduction  the  same  way  from  any  pressure;  just  as  long 
as  you  do  not  make  a  brake  pipe  reduction  that  will  cause 
the  brake  cylinder  and  auxiliary  to  equalize,  or  when  you 
do  that  it  stops  the  auxiliary  reduction.  A  10  pound 
reduction  from  90  gives  just  the  same  pressure  as  at  any 
lower  pressure  till  you  reach  the  equalizing  pressure, 
which  is  usually  below  50.  The  next  10  pound  reduction 
from  the  auxiliary  into  this  cylinder  of  air  having  a 
pressure  of  23  pounds  will  show  a  greater  proportionate 
raise  on  the  gage,  for  the  first  reduction  had  to  fill  the 
cylinder  from  the  vacuum  line  up  to  gage  pressure— 15 
pounds- — the  second  one  had  this  work  done  for  it,  and 
therefore  made  a  better  showing  on  the  gage. 

When  making  tests  the  gage  will  not  always  show 
these  exact  amounts,  as  the  leakage  groove  uses  consider- 
able air,  auxiliaries  are  not  all  the  size  specified,  the  clear- 
ance in  the  end  of  cylinder  varies,  and  the  expansion  of 
air  lowers  the  temperature,  which  alters  the  pressure. 

The  question  of  the  fall  of  temperature  is  not  taken 


SIZE     OF    RESERVOIRS  189 

into  consideration  in  these  calculations,  as  the  temperature 
of  the  air  in  the  brake  equipment  on  a  car  is  very  close 
to  that  of  the  atmosphere  at  all  times. 

To  get  the  area  of  the  piston,  multiply  the  diameter  by 
itself  and  that  product  by  .7854.  To  get  the  volume  of  the 
cylinder,  multiply  this  area  by  the  piston  travel  and  add 
the  clearance.  This  clearance  consists  of  the  space  between 
piston  and  pressure  head,  usually  $/%  of  an  inch,  the  pipe 
between  the  triple  and  the  cylinder  and  the  space  in  the 
triple  valve  that  is  filled  with  brake  cylinder  air. 

Reservoirs  are  so  constructed  that  it  is  difficult  to  cal- 
culate their  exact  volume  from  their  outside  dimensions, 
this  can  be  obtained  exactly  by  weighing  them  while 
empty,  then  filling  full  of  water  and  weighing  again;  the 
difference  in  weight  will  be  the  amount  of  water  contained. 
A  pound  of  water  at  62  degrees  occupies  27.71  cubic 
inches;  one  cubic  foot  weighs  62.355  pounds. 

A  cast  iron  auxiliary  for  an  8-inch  freight  brake  holds 
about  1,620  cubic  inches. 

10  x  24  in.  wrought  iron  auxiliary  1.510  cubic  in. 

12  x  33  in.  wrought  iron  auxiliary  3.030  cubic  in. 

14  x  33  in.  wrought  iron  auxiliary  4.120  cubic  in. 

16x33  in.  wrought  iron  auxiliary  5.322  cubic  in. 

The  equalizing  reservoir  from  590  to  621  cu.  in.  the 
later  pattern  10x14^4  inches  long,  hold  800  cu.  in.  A 
freight  car  has  about  640  cu.  in.  in  the  brake  pipe,  hose, 
cross-over  pipe  and  triple  valve  to  the  bottom  of  the 
triple  piston — all  this  space  contains  brake  pipe  air. 

Main  reservoirs  vary  in  size  to  suit  their  location  on 
the  engine,  when  of  sufficient  volume  there  are  usually 
more  than  one,  having  the  air  from  the  pump  passing 
into  the  first  one,  from  there  to  the  next,  and  so  on  to  the 
brake  valve.  This  gives  the  air  a  chance  to  cool  down  to 
the  normal  temperature  of  the  atmosphere,  when  it  will 
deposit  all  its  moisture  as  water  in  the  main  reservoir.  If 
the  air  passes  through  the  brake  valve  without  cooling 
down  it  will  leave  some  of  the  water  in  the  brake  pipe — 


190  TEMPERATURE    OF    AIR   DURING    COMPRESSION 

see  question  8 — and  give  trouble  in  the  operation  of  the 
brake. 

Main  reservoirs  should  have  a  volume  of  at  least 
20,000  cubic  inches.  Freight  engines  should  have  1,000 
cubic  inches  capacity  for  each  car  in  the  train.  An  engine 
that  can  handle  a  75-car  train  should  have  75,000  cubic 
inches.  Large  main  reservoir  capacity  is  necessary  to 
promptly  release  all  brakes  on  a  long  train  and  will  in  a 
measure  prevent  stuck  brakes  and  slid  flat  wheels  on  the 
rear  cars — see  question  9.  A  large  main  reservoir  also 
tends  to  save  a  pump,  as  it  can  run  at  a  slower  speed,  for 
it  can  run  continuously,  not  intermittently. 

When  air  at  a  temperature  of  60  degrees  is  compressed 
from  the  atmosphere  line  up  to  a  gage  pressure  of  70 
pounds  the  temperature  rises  to  about  400  degrees;  with  a 
pressure  of  90  pounds  it  is  about  450  degrees,  at  105 
pounds  it  is  490  degrees.  As  this  heat  is  the  result  of  the 
mechanical  energy  of  the  steam  developed  through  the  air 
pump,  you  can  readily  see  that  it  takes  more  power  from 
the  boiler  to  reach  a  high  pressure  than  a  moderate  one. 
Also  the  air  piston  will  come  nearer  the  end  of  its  stroke 
before  the  air  is  compressed  to  105  than  at  90  pounds,  so 
that  a  less  amount  of  105-pound  air  is  delivered  than  of 
90.  As  the  air  usually  cools  off  to  the  normal  tempera- 
ture before  it  passes  into  the  brake  cylinder,  we  can  take 
no  advantage  of  any  expansion  of  air  by  the  heat  of 
compression. 

The  heat  that  is  given  out  by  compression  is  taken  up 
when  the  air  is  allowed  to  expand.  When  air  expands 
through  any  opening  from  a  high  to  a  low  pressure  it 
takes  up  or  absorbs  heat  from  all  surrounding  bodies,  this 
accounts  ^for  its  being  so  cool  when  coming  out  of  the 
bleed  cock,  exhaust  port  of  a  triple  or  exhaust  pipe  of  an 
engine  run  by  compressed  air,  in  some  cases  it  will  form 
ice. 

When  studying  the  equalizing  processes  in  the  opera- 
tion of  compressed  air  equipment,  remember  that  it  is  air 
that  flows  from  one  part  of  the  equipment  to  another  and 


THE  NEW   YORK  AIR  BRAKE  191 

not  pressure.  Pressure  is  a  condition,  air  is  a  substance 
or  material.  When  air  flows  from  the  auxiliary  to  the 
cylinder  it  will  change  the  conditions  or  pressure  in  these 
places,  but  the  pressure  does  not  flow  either  way. 

It  will  take  away  much  of  the  mystery  of  equalization 
if  you  bear  these  facts  in  mind. 


THE   NEW  YORK   AIR   BRAKE 

The  important  parts  of  the  New  York  Air  Brake  that 
differ  from  those  of  the  Westinghouse  Automatic  Brake, 
are  the  Duplex  Air  Pump;  Governor;  Engineer's  Valves; 
Compensating  Valve;  Quick- Action  Triple  Valve;  Air 
Signal  Valve  and  Brake  Pipe  Strainer.  The  Brake  Cylin- 
ders and  pistons  in  all  their  details;  Reservoirs,  both  main 
and  auxiliary;  Pressure  Retaining  Valves;  Reducing  Valve 
for  the  air  signal  system;  Brake  Pipe  with  Hose  Coup- 
lings, Angle  and  Cut-out  Cocks  and  Conductor's  Valves 
are  the  same  in  both  systems  of  equipment;  their  con- 
struction and  operation  have  already  been  described  in 
this  book. 

As  freight  cars  in  interchange  service  are  moved  from 
one  railroad  to  another  v/hen  of  the  same  gage,  there 
will  be  in  all  freight  trains  some  cars  equipped  with  the 
Westinghouse  and  others  with  the  New  York  brake.  The 
Master  Car  Builders'  specifications  require  that  all  brakes 
in  a  train  shall  be  so  constructed  that  the  different  kinds 
will  operate  in  unison,  so  as  to  control  the  speed  of  the 
train  without  shocks.  For  that  reason  the  general  rules 
for  the  handling  of  trains  are  the  same,  whichever  brake 
is  used.  There  are  several  differences  in  the  construction 
of  these  two  kinds  of  brake  equipment,  that  give  different 
results  when  they  are  operated;  these  points  will  be 
explained  later  on. 


TRIPE 

FROM  BOILER 


THE   DUPLEX   AIR   PUMP 

This  pump  has  two  steam  cylinders,  1  and  2,  and  two 
air  cylinders,  3  and  4 ;  the  steam  valves,  5  and  6,  being 
operated  by  reversing  or  tappet  rods,  8-8.  These  tappet 
rods  are  operated  by  the  tappet  plates  20,  which  are 
securely  fastened  to  the  lower  side  of  each  steam  piston 
by  bolts  55.  The  steam  cylinders  each  receive  steam  from 
the  boiler  and  exhaust  to  the  atmosphere,  the  air  cylinders 
each  receive  free  air  from  the  atmosphere;  but  the  air 
in  cylinder  4  when  compressed  passes  into  cylinder  3  and 
from  there  is  forced  into  the  main  reservoir.  Thus,  the 
air  cylinders  compound  the  air,  while  the  steam  cylinders 
work  simple.  Each  steam  cylinder  of  the  No.  2  pump  is 
7  inches  in  diameter  and  9  inches  stroke,  the  low  pressure 
air  cylinder  4  is  10  inches  in  diameter,  the  high  pressure 
air  cylinder  3  is  7  inches  in  diameter;  both  cylinders  have 
the  same  stroke  as  the  steam  cylinders,  9  inches.  The 
volume  .of  air  cylinder  4  is  twice  that  of  cylinder  3. 

The  sectional  view  shows  the  pump  with  all  parts  in 
the  position  when  making  its  first  stroke  after  turning  on 
steam,  steam  piston  21  and  air  piston  32  which  are  con- 
nected by  piston  rod  18,  having  made  a  little  over  half 
their  up  stroke.  At  the  bottom  is  shown  the  new  style  of 
main  steam  valve,  a  piston  valve  instead  of  a  slide  valve. 

Live  steam  comes  from  the  boiler  through  the  steam 
pipe  and  governor  and  into  steam  head  19  and  passes 
into  each  steam  chest  around  steam  valves  5  and  6.  This 
steam  passage  is  shown  by  dotted  lines  from  56  on  each 
side  of  number  19.  A  drain  cock,  54,  is  tapped  into  this 
passage  to  allow  condensed  water  to  be  blown  out  when 
first  starting  up  the  pump,  at  all  other  times  while  the 
pump  is  running  it  should  be  closed.  The  exhaust  passage 
is  shown  leading  from  exhaust  cavities  of  the  slide  valves 
5  and  6  through  58.  Under  58  comes  the  drain  cock  for 
the  exhaust;  unless  the  pump  sets  high  enough  so  all  con- 
densed water  will  drain  to  the  smoke  arch  end,  this  cock 
can  be  left  open  if  so  desired,  providing  there  is  a  drip 


194  OPERATION    OF    DUPLEX    PUMP 

pipe  leading  to  the  ash  pan.  The  steam  head  is  made 
with  right  and  left  side  connections  for  live  and  exhaust 
steam,  the  openings  not  used  are  closed  with  threaded 
plugs. 

When  steam  is  shut  off  from  the  pump,  there  being  no 
pressure  on  the  back  of  the  valves  5  and  6,  they  drop  to 
their  lowest  position  as  shown.  Live  steam  when  first 
turned  on  passes  up  through  port  23-24  into  cylinder  1, 
and  if  piston  22  is  not  already  at  the  bottom  of  its  cylinder 
1,  it  is  forced  down  and  held  there.  At  the  same  time  live 
steam  passes  through  port  26  under  piston  21,  forcing  it 
and  air  piston  32  upwards;  air  in  cylinder  4  above  piston 
32  raises  valve  11  and  passes  into  upper  end  of  high 
pressure  air  cylinder  3  above  piston  31.  At  the  same  time 
while  piston  32  is  moving  up,  free  air  from  outside  raises 
inlet  valve  10,  passing  into  lower  end  of  low-pressure 
cylinder  4  and  filling  it  ready  for  compression  on  down 
stroke  of  its  piston.  Piston  21  then  remains  at  top  of  its 
stroke  till  the  other  steam  piston  makes  an  up  stroke. 

When  steam  piston  21  approaches  the  top  limit  of  its 
stroke,  tappet  plate  20  catches  the  button  on  the  top  end  of 
the  reversing  or  tappet  rod  8,  drawing  this  rod  and  slide 
valve  6  up  so  that  port  27  is  uncovered  to  the  live  steam 
and  port  23-24-25  is  connected  to  the  exhaust.  With  live 
steam  passing  under  it  and  the  upper  side  connected  to  the 
exhaust,  piston  22  moves  upward,  carrying  air  piston  31 
with  it  and  forcing  the  air  in  upper  end  of  the  high-press- 
ure cylinder  past  the  final  discharge  valve  13  into  the 
main  reservoir.  At  the  same  time,  air  from  the  atmos- 
phere flows  in  past  valves  10  and  12,  filling  the  lower 
end  of  the  high-pressure  cylinder  3  with  free  air.  The 
low-pressure  air  cylinder  has  one  inlet  valve  for  each  end, 
9  and  10;  the  high-pressure  air  cylinder  has  to  draw  its 
supply  of  free  air  through  two  inlet  valves  at  each  end, 
9  and  11  at  the  top  end  and  10  and  12  at  the  bottom. 
Valves  11  and  12  are  the  discharge  valves  for  the  low- 
pressure  cylinder;  13  and  14  are  the  final  discharge  valves 
from  the  high-pressure  cylinder  to  the  main  reservoir. 


OPERATION    OF    DUPLEX    PUMP  195 

As  piston  22  nears  the  end  of  its  up  stroke,  the  tappet 
plate  moves  rod  8  up,  drawing  valve  5  upwards,  this  con- 
nects port  26  with  the  exhaust  so  that  the  steam  in 
cylinder  2  under  piston  21  will  pass  out;  port  28-29-30  is 
opened  and  live  steam  passes  in  above  piston  21,  forcing 
it  down,  bringing  air  piston  32  with  it  and  compressing 
the  air  in  the  lower  end  of  cylinder  4  past  valve  12  into 
the  lower  end  of  high-pressure  cylinder  3,  and  drawing 
a  supply  of  free  air  past  valve  9  into  the  upper  end  of 
cylinder  4.  During  this  downward  movement  .of  piston 
21,  piston  22  is  stationary  at  the  top  of  its  stroke.  As 
piston  21  nears  the  bottom  limit  of  its  stroke,  tappet  plate 
20  strikes  the  shoulder  on  rod  8,  moving  it  and  steam 
valve  6  to  their  lower  position;  this  opens  port  23-24  to 
live  steam  and  27  to  the  exhaust;  steam  piston  22  then  is 
forced  down,  bringing  air  piston  31  with  it;  the  air  in  the 
lower  end  of  cylinder  3  is  forced  past  final  discharge 
valve  14  to  the  main  reservoir,  free  air  from  the  atmos- 
phere passes  by  valves  9  and  11  and  fills  the  upper  end 
of  cylinder  3.  This  completes  a  round  trip  of  both  steam 
and  air  pistons. 

By  means  of  the  tappet  rod  each  steam  piston  moves 
the  steam  valve  that  opens  and  closes  the  steam  and 
exhaust  ports  for  the  other  cylinder,  so  that  when  one 
steam  piston  completes  its  stroke  it  has  moved  the  steam 
valve  to  operate  the  other  steam  piston  and  then  remains 
at  the  end  of  its  stroke  while  the  other  piston  makes  one. 
This  ensures  that  the  air  pistons  make  a  full  stroke  and 
leave  no  clearance  space  at  the  ends  of  the  air  cylinders, 
except  the  volume  of  the  passages  to  the  discharge  valves 
and  leaves  the  air  pistons  in  the  proper  position  so  the 
air  from  the  low-pressure  cylinder  can  pass  into  the  high- 
pressure  cylinder  ready  for  the  final  compression  to  the 
main  reservoir.  All  the  air  valves  have  a  lift  of  1/16 
of  an  inch.  Oil  cups  54  are  in  the  top  heads  of  each 
air  cylinder. 

The  No.  6  Duplex  Pump  here  shown  has  the  steam 
end  constructed  in  much  the  same  manner  as  the  No.  2 


NO.  6  DUPLEX  AIR  PUMP. 


ALL  AIR  VAI 
" 


DUPLEX     PUMP  197 

Duplex  Pump.  The  air  inlet  and  discharge  valves  are 
placed  in  another  manner,  the  No.  6  pump  has  a  separate 
air  inlet  for  each  cylinder  to  take  in  atmospheric  air,  their 
location  is  shown  in  the  cuts  of  the  top  end  of  the  pump 
and  the  sectional  view.  The  bore  and  stroke  of  each 
cylinder  is  shown  in  the  cuts  as  well  as  the  course  of  the 
steam  and  air  by  the  arrows,  during  the  first  up  stroke.  A 
description  of  the  No.  6  is  not  necessary  here,  as  with  the 
description  of  the  No.  2  pump  and  the  illustrations,  the 
operation  of  the  pump  can  be  readily  understood.  The 
low-pressure  cylinder  takes  in  air  from  the  atmosphere 
at  each  stroke  of  its  piston  32  and  delivers  the  compressed 
air  to  the  high-pressure  cylinder  through  the  intermediate 
valves  11  and  12.  At  each  stroke  of  the  high-pressure 
piston  31  it  takes  in  a  supply  of  air  from  the  atmosphere 
through  its  inlet,  valves  15  or  16  and  afterwards  receives 
the  air  from  the  low-pressure  cylinder  in  addition  to  the 
free  air  taken  in.  The  defects  of  this  pump  are  treated 
in  the  same  manner  as  those  of  the  No.  2.  Leaks  at  the 
inlet  valves  are  more  easily  located  with  the  No.  6  than 
the  No.  2,  as  there  is  a  separate  strainer  for  each  inlet 
with  the  No.  6. 


DEFECTS  OF  THE  DUPLEX  PUMP 

When  the  Duplex  pump  stops,  first  open  drain  cock  54, 
if  steam  blows  out  strong  the  governor  is  all  right.  If 
very  little  steam  passes  out,  examine  the  governor.  If  the 
button  breaks  off  tappet  rod  8,  or  tappet  plate  20  gets 
worn  badly  or  very  loose,  the  steam  piston  on  that  side 
will  make  its  up  stroke,  but  the  slide  valve  will  not  be 
raised  up  to  open  and  close  the  steam  and  exhaust  ports 
for  the  other  cylinder.  If  the  tappet  rod  is  broken  on  the 
high-pressure  side,  both  air  pistons  will  stop  at  the  top 
of  their  stroke;  if  the  tappet  rod  is  disabled  on  the  low- 
pressure  side,  piston  21  can  move  to  the  top  of  its  stroke, 
but  valve  6  will  not  be  moved  up,  steam  will  hold  piston 


198  DUPLEX    PUMP    DEFECTS 

22  and  air  piston  31  at  the  bottom  of  their  strokes. 
Taking  off  cap  nuts  15  will  soon  locate  which  tappet  rod 
is  at  fault.  To  locate  at  which  end  of  the  stroke  the  air 
piston  has  •  stopped,  remove  the  oil  cups  from  the  top  of 
air  cylinders  and  run  a  piece  of  wire  down  to  the  piston. 
If  the  nuts  74  work  loose  and  strike  the  top  head  so  the 
piston  can  not  make  a  full  stroke,  the  steam  valve  on  that 
side  will  not  be  moved  to  change  the  course  of  steam  to 
the  other  cylinder,  and  the  other  piston  will  not  move. 
This  defect  acts  like  a  button  broken  off;  it  can  be 
located  by  taking  top  head  47  off. 

Worn  air  piston  packing  rings  will  allow  the  pump  to 
run  very  fast  and  not  make  much  air;  it  will  run  hotter 
than  usual  and  pound  badly.  The  air  cushion  necessary 
to  keep  the  air  pistons  from  striking  the  heads  will  be 
lost;  this  will  cause  the  pound.  Leakage  of  air  around 
the  high-pressure  piston  rod  will  waste  the  air  already 
compressed,  and  allow  the  piston  to  strike  the  lower  head; 
it  will  also  make  the  strokes  uneven.  To  locate  worn 
air  piston  packing  rings,  run  the  pump  very  slowly  against 
full  pressure  in  the  main  reservoir.  If  the  rings  leak  con- 
siderable, compressed  air  will  get  past  the  piston  in  the 
latter  part  of  its  stroke;  this  will  reduce  to  nothing  the 
amount  of  free  air  drawn  in  at  the  inlet  valves.  To 
locate  the  defective  piston,  note  which  one  in  making  its 
stroke  is  not  drawing  in  air  properly.  This  is  not  a  very 
good  test  for  the  high-pressure  piston,  as  it  may  be  draw- 
ing part  of  its  supply  from  the  low-pressure  cylinder, 
which  has  been  expanded  by  the  heat  of  the  cylinder.  If 
the  pump  works  all  right  at  a  low  air  pressure,  and  as  the 
pressure  increases  the  low-pressure  cylinder  seems  to  be 
doing  most  of  the  work,  examine  the  high-pressure  side 
to  see  why  it  is  not  doing  its  share.  The  low-pressure 
piston  ordinarily  works  against  a  pressure  of  three 
atmospheres — 30  pounds  gage  pressure,  which  is  the  press- 
ure on  the  high-pressure  piston  at  the  beginning  of  its 
stroke  when  both  cylinders  have  rilled  full  of  free  air  from 
the  atmosphere. 


DUPLEX     PUMP    DEFECTS  199 

If  an  inlet  or  receiving  valve  9  or  10  leaks,  the  air 
will  blow  out  past  it  as  piston  32  moves  towards  it.  Both 
valves  9-11  or  10-12  will  have  to  leak  if  any  air  gets 
back  to  the  atmosphere  from  the  high-pressure  cylinder. 
Open  the  04!  cup  on  the  low-pressure  cylinder,  run  the 
pump  slowly  against  the  full  reservoir  pressure ;  if  valve 
11  leaks  when  the  high-pressure  piston  is  moving  up  air 
will  pass  valve  11  and  blow  out  of  the  oil  cup.  If  final 
discharge  valve  13  leaks,  stop  the  pump,  opening  the  oil 
cup  on  the  high-pressure  cylinder  will  show  it.  If  valve 
14  leaks,  the  piston,  if  not  at  the  top  of  cylinder  3,  will 
move  up  there  unless  the  air  can  blow  out  around  the 
pistcfn  rod.  Leaky  air  inlet  valves  will  cause  the  pump 
to  make  irregular  strokes,  quick  towards  the  leaky  valve 
and  slow  away  from  them.  If  discharge  valves  leak,  the 
piston  will  move  slowly  towards  the  leaky  valve  and 
quickly  away  from  it.  A  leak  by  the  gasket  48  will  show 
like  a  leaky  air  valve ;  to  be  sure  which  it  is,  the  best  way 
is  to  take  up  head  47  and  examine  the  gasket  and  air 
valves.  When  the  air  valves  or  their  seats  have  worn  so 
as  to  materially  increase  the  lift  or  allow  them  to  leak, 
it  is  best  to  put  in  new  valves  and  seats  that  are  in  perfect 
order.  When  new  valves  are  placed  in  the  old  seats  or  the 
old  valves  ground  in  to  a  fit,  be  careful  that  the  lower 
end  of  the  wings  of  the  valve  does  not  strike  on  the 
cages  or  the  stops  of  the  valves  under  them. 

The  exhausts  from  the  pump  when  run  very  slowly 
against  standard  pressure,  will  usually  show  where  the 
air  leaks  are  located. 

Leaky  steam  piston  packing  rings  will  cause  an  inter- 
mittent blow.  Run  the  pump  slowly  against  full  air 
pressure,  open  the  drain  cock  in  the  exhaust  at  58;  you 
can  soon  locate  the  defect.  A  leaky  steam  valve  will 
usually  give  a  steady  blow. 

Steam  escaping  at  the  piston  rod  packing  is  liable  to 
be  drawn  in  at  the  air  inlet  valves,  and  fill  the  equipment 
with  water;  this  is  very  dangerous  in  cold  weather. 


THE   PUMP   GOVERNOR 

The  New  York  Air  Brake  Co.  make  three  styles  of 
governors :  the  Single,  Duplex  and  Triplex.  As  these 
only  vary  in  the  number  of  air  diaphram  bodies  attached 
to  a  single  steam  valve  body,  we  will  describe  the  Duplex 
governor,  which  is  the  one  most  generally  used.  Air 
enters  the  governor  at  c  from  the  brake  pipe  to  one 
diaphram  body  and  from  the  main  reservoir  to  the  other 
diaphram  body.  At  f  is  a  strainer  to  prevent  dirt  or  grit 

Duplex  Governor. 

PLATE  Q  8. 


passing  from  e  into  chamber  A.  Air  passes  into  the 
chamber  A  under  the  corrugated  diaphram  13,  which  is 
held  down  on  its  seat  14  by  a  regulating  spring  10,  acting 
on  the  diaphram  button  12.  When  the  air  pressure  under 


OPERATION    OF    PUMP    GOVERNOR  201 

the  diaphram  exceeds  the  resistance  of  the  spring  10, 
the  diaphram  is  raised  off  its  seat  on  14,  this  allows  air 
at  the  brake  pipe  pressure  to  pass  down  through  a  and 
C  into  B  on  top  of  piston  4,  which  at  once  moves  down, 
also  moving  steam  valve  5  down  against  its  seat  and  shut- 
ting off  the  supply  of  steam  from  the  boiler  to  the  pump. 
A  small  hole  at  o  lets  a  little  steam  pass  through  to  the 
pump  so  it  will  make  a  stroke  at  intervals.  A  vent  port 
V  in  the  cylinder  1  over  piston  4  allows  air  to  blow  out 
steadily  while  the  air  pressure  is  operating  the  governor, 
this  also  tends  to  keep  the  pump  moving.  When  the  air 
pressure  drops  so  that  spring  10  can  hold  diaphram  13 
on  its  seat,  the  air  escapes  from  chamber  B  over  piston 

4  through  vent  V\  valve  5  and  piston  4  are  raised  by  the 
steam  pressure  and  the  steam  again  passes  to  the  pump. 
When  valve  5   is   at  the  top  of  its   travel   a   steam   tight 
seat  is  at  S,  so  no  steam  can  work  up  under  the  piston  4. 
The  dotted  lines  at  x  show  the  location  of  the  drip  open- 
ing in  the  side  of  the  cylinder  1,  which  allows  any  steam 
that  works  up  past  valve  5   or   air  that  comes   down  by 
packing  ring  24  to  escape  to  the  atmosphere.     When  valve 

5  is  partly  open,  steam  can  blow  out  at  the  drip  steadily 
as  its  stem  does  not  make  a  steam  tight  fit  in  the  guide  6. 
The  regulating  springs  over  the  air  diaphrams  are  adjusted 
by  the  small  adjusting  screw  8  and  fastened  by  the  jam 
nut  9. 

The  later  pattern  of  governors  have  a  large  adjusting 
nut,  it  is  shown  in  the  Duplex  Controller. 

The  single  governor  is  usually  set  at  70  pounds,  as  it 
controls  the  brake  pipe  pressure  and  is  piped  to  passage 
E  in  the  brake  valve  on  the  brake  pipe  side  of  the  excess 
pressure  valve  97. 

The  Duplex  governor  has  the  low-pressure  air  dia- 
phram chamber  connected  to  the  brake  pipe  or  chamber  A 
of  the  brake  valve,  the  opening  into  E  of  the  brake  valve 
must  be  plugged,  and  main  reservoir  air  to  the  high- 
pressure  side.  The  brake  pipe  side  is  set  at  70  pounds 
and  the  main  reservoir  side  at  90.  With  this  arrangement, 


202  PIPING      THE     GOVERNOR 

if  the  governor  diaphrams  are  not  set  for  the  proper 
pressures,  the  brake  pipe  pressures  in  running  and  full 
release  positions  will  not  be  right. 

With  the  Double  Pressure  system,  where  a  low  brake 
pipe  pressure  is  carried  with  empty  cars  and  a  higher  one 
with  loaded  cars,  both  sides  of  the  duplex  governor  are 
piped  to  the  opening  E.  In  the  pipe  leading  to  the  low- 
pressure  side  of  the  governor  there  is  a  cut-out  cock, 
when  this  is  shut  the  higher  brake  pipe  pressure  will  be 
carried. 

With  the  Triplex  governor  one  air  diaphram  is  con- 
nected to  the  brake  pipe  and  set  at  one  standard  pressure, 
the  second  diaphram  is  set  for  a  higher  brake  pipe  press- 
ure, and  the  third  diaphram  is  connected  to  the  main 
reservoir  air  and  set  at  the  pressure  desired  there.  There 
is  a  cut-out  cock  in  the  air  pipe  leading  to  the  lowest 
brake  pipe  diaphram,  which  can  be  closed  when  necessary 
to  carry  a  higher  brake  pipe  pressure;  this  cuts  the  lowest 
one  out  of  service.  The  diaphram  13  gets  gummed  up  on 
the  seat  of  14  so  that  in  some  cases  air  leaks  by  it  and  the 
governor  piston  is  operated  before  the  proper  pressure  is 
reached.  Or  it  may  get  gummed  up  so  much  that  air 
can  not  pass  down  to  the  piston.  For  defects  common 
to  governors,  see  front  of  book. 


THE  1902  MODEL    BRAKE   VALVE 

The  duty  of  the  brake  valve  is  to  control  the  passage  of 
air  from  the  main  reservoir  to  the  brake  pipe;  from  the 
brake  pipe  to  the  atmosphere  or  stop  the  flow  of  air 
through  it  in  any  direction.  The  engineer's  brake  valve, 
when  in  full  release  position,  should  allow  the  main 
reservoir  air  to  flow  directly  to  the  brake  pipe  through 
large  ports  to  equalize  these  pressures  quickly.  It  should 
allow  the  air  to  pass  through  smaller  openings  in  running 
position  and  maintain  a  higher  pressure  in  the  main 
reservoir  after  the  brake  pipe  pressure  has  reached  a 
standard  amount.  It  should  have  a  moderate  opening 


Engineer's  Br&ke  VaJve. 
1902  MODEL. 


FACE  OF  SLIDE  VALVE 
K 


167 


204  1902    MODEL    BRAKE    VALVE 

for  the  brake  pipe  air  to  pass  to  the  atmosphere  in  a 
graduated  service  application,  and  should  automatically 
close  the  opening  when  the  brake  pipe  pressure  has  been 
reduced  the  desired  amount  to  operate  the  triples  with 
a  graduated  application.  It  should  also  have  a  large  and 
direct  opening  to  the  atmosphere  to  exhaust  the  brake 
pipe  air  quickly  in  an  emergency,  so  the  triples  will  oper- 
ate quick-action. 

The  New  York  Brake*  Valve  is  shown  in  a"  sectional 
view.  The  brake  valve  body,  101-A,  contains  a  main  slide 
valve,  114-A,  which  is  moved  back  and  forth  over  the 
slide  valve  seat  by  the  slide  lever  118  and  links  116;  this 
lever  is  attached  to  lever  shaft  120,  and  moved  by  handle 
123.  Plugs  96  can  be  taken  out  to  oil  the  slide  valve  114. 
Main  reservoir  air  enters  the  body  of  the  valve,  passing 
up  into  chamber  B,  and  is  all  around  the  sides  and  on  top 
of  slide  valve  114-A.  It  also  passes  to  the  red  hand  of 
the  gage  and  to  the  high  pressure  side  of  the  duplex 
governor.  The  black  hand  gets  air  from  the  brake  pipe 
side  of  the  brake  valve.  When  this  valve  is  in  full  re- 
lease position,  main  reservoir  air  passes  directly  through 
the  port  a  into  chamber  A,  which  is  connected  with  the 
brake  pipe  directly,  so  that  in  this  position  main  reservoir 
air  can  equalize  with  the  brake  pipe;  if  the  duplex  gage 
is  right  both  hands  will  show  the  same  pressure.  When 
the  handle  123  is  moved  back  to  running  position,  port  a 
is  covered  by  the  end  of  the  slide  valve  so  no  air  can  pass 
through  a;  main  reservoir  air  must  then  pass  from  B 
under  excess  pressure  valve  97,  raise  it  against  the  stiffness 
of  its  spring  90,  pass  through  E  into  the  cavities  M-M 
in  the  face  of  the  slide  valve  and  through  a  into  A.  Brake 
pipe  pressure  is  also  holding  valve  97  down  in  addition 
to  the  stiffness  of  spring  90,  so  that  with  main  reservoir 
pressure  on  one  side  and  brake  pipe  pressure  on  the 
other  side  of  97,  spring  90  is  able  to  maintain  a  steady 
difference  in  these  pressures,  at  whatever  amount  the 
main  reservoir  pressure  may  be.  This  difference  is  usually 
20  pounds. 


1902  MODEL  BRAKE  VALVE 


205 


Two  sectional  views  are  shown  giving  the  position  of 
the  excess  pressure  valve  97,  the  ports  from  B  to  E, 
and  showing  the  main  reservoir,  brake  pipe  and  gage 
connections.  The  connection  to  the  supplementary  reser- 
voir and  port  H  is  shown  on  the  side  elevation. 

In  the  lower  part  of  the  valve  body,  101-A,  is  a  piston, 
104-A,  moving  in  a  bushing;  this  piston  by  means  of  the 


|  RESERVOIR 


graduating  valve  lever  112,  can  move  the  graduating  or 
'cut-off  valve  110,  which  rests  against  the  lower  face  of 
slide  valve  114-A,  and  in  its  normal  position  covers  the 
port  F  that  is  connected  by  a  passage  through  the  middle 
of  the  slide  valve  with  port  G,  which  in  service  position  is 
open  to  the  atmosphere  through  cavity  C.  When  the  slide 
valve  is  moved  to  the  first  notch  in  service  application 
position,  brake  pipe  air  can  flow  from  A  through  a,  ports 
F  and  G  into  C,  and  reduce  the  brake  pipe  pressure. 
Chamber  D  on  the  other  side  of  the  piston  104-A  is  con- 
nected with  the  supplementary  reservoir  155,  which  has  a 
pressure  in  it  at  the  beginning  of  the  brake  pipe  reduction 


206  OPERATION    OF    BRAKE    VALVE 

equal  to  that  in  the  brake  pipe.  As  the  brake  pipe  press- 
ure is  reduced,  the  air  in  chamber  D  and  155  expands, 
and  moves  piston  104-A  towards  the  reducing  brake  pipe 
pressure  in  A,  this  in  turn  moves  cut-off  valve  110  back 
and  closes  port  F,  thus  cutting  off  the  flow  of  brake  pipe 
air  to  the  atmosphere,  without  any  movement  of  the 
handle  123  to  lap  position;  this  is  expected  to  reduce  the 
brake  pipe  pressure  about  4  pounds.  A  further  movement 
of  handle  123  to  the  next  service  notch  will  move  valve 
114-A  so  that  port  F  will  be  again  opened;  when  the 
proper  reduction  has  been  made,  cut-off  valve  will  again 
close  port  F.  Successive  reductions  can  be  made  by 
moving  handle  123  to  the  next  service  notch  till  the  last 
one  is  reached,  when  the  brake  pipe  pressure  will  have 
been  reduced  about  23  pounds,  and  the  brakes  applied 
in  full  service.  The  size  of  the  supplementary  reservoir  is 
such  that  when  the  air  in  it  expands  into  the  additional 
space  made  when  piston  104-A  moves  clear  forward,  the 
pressure  will  be  reduced  from  70  to  about  47  pounds,  or  a 
little  over  two-sevenths  of  the  original  pressure;  with  a 
higher  pressure  the  total  reduction  will  be  greater. 

To  reduce  the  brake  pipe  pressure  suddenly  and 
directly,  123  is  moved  at  once  to  the  emergency  position ; 
this  opens  the  large  ports  J-J  to  A  so  that  brake  pipe  air 
passes  through  two  passages ;  one  on  each  side  of  F-G 
and  out  at  K  to  C.  This  sudden  discharge  of  brake  pipe 
air  through  the  large  openings  will  reduce  the  pressure 
quickly  and  operate  the  triples  quick-action.  After  any- 
application,  whether  service  or  emergency,  the  brake  valve 
should  be  placed  in  full  release  position  till  the  brake  pipe 
has  been  charged  its  full  length,  and  all  triples  moved  to 
release  position,  if  it  is  desired  to  release  all  brakes 
properly. 

If  piston  104-A  has  been  moved  forward  by  the  press- 
ure in  chamber  D  at  the  time  of  a  reduction  of  brake  pipe 
pressure,  it  must  be  moved  back  to  its  normal  position 
when  the  brakes  are  released  if  it  is  to  be  ready  to  move 
cut-off  valve  110  to  graduate  the  next  brake  pipe  reduc- 


OPERATION    OF    BRAKE    VALVE  207 

tion.  To  do  this  some  of  the  air  in  chamber  D  and  reser- 
voir 155  must  be  discharged  to  the  atmosphere.  This  is 
done  through  port  and  passage  O,  which  passes  through 
the  valve  cover  115-A  as  shown  in  illustrations,  back 
into  the  valve  body  101-A  and  out  to  C  through  port  J 
when  the  valve  is  in  full  release,  or  through  cavity  P  in 
the  slide  valve  when  in  running  or  lap  position.  Another 
passage,  H,  connects  chamber  D  at  all  times  with  reservoir 
155,  so  that  when  air  can  pass  out  of  chamber  D  through 
O,  it  can  also  pass  out  of  reservoir  155.  With  air  exhaust- 
ing from  chamber  D  and  brake  pipe  pressure  in  A,  piston 
104-A  is  at  once  moved  back  to  its  normal  position;  also- 
moving  cut-off  valve  110.  In  the  end  of  piston  104-A 
is  a  valve,  180,  that  closes  port  O  when  the  piston  is  in 
the  normal  position  and  the  brake  valve  in  full  release,, 
running  position  or  lap,  and  prevents  any  air  from  chamber 
D  flowing  out  at  port  O*  Air  from  the  brake  pipe  can 
flow  from  A  up  past  ball  valve  184,  and  recharge  chamber 
D  at  all  times  when  the  pressure  is  less  in  D  than  in  A; 
but  cannot  flow  back  into  A  as  the  valve  184  prevents  this. 
This  recharges  chamber  D  and  reservoir  155  as  soon  as- 
piston  104-A  moves  to  normal  position  and  seats  valve 
180,  closing  passage  O.  The  opening  past  ball  valve  184 
and  through  the  piston  into  chamber  D,  is  much  smaller 
than  O,  so  chamber  D  air  can  be  exhausted  through  O 
faster  than  it  can  feed  in  at  184,  this  ensures  the  move- 
ment of  piston  to  its  normal  position.  The  older  pattern 
of  Vaughn-McKee  valve  does  not  have  this  recharging 
attachment,  and  in  all  cases  in  releasing  brakes  the  valve 
must  be  replaced  in  full  release  an  instant  to  discharge 
the  air  from  chamber  D,  then  moved  to  running  position 
to  recharge  chamber  D,  in  order  to  get  the  graduating 
action  of  piston  104. 

As  the  supplementary  reservoir  is  supplied  with  air 
from  the  brake  pipe,  while  this  reservoir  is  charging  after 
an  application  and  release  of  the  brake  on  a  lone  engine 
with  the  older  type  of  the  Vaughn-McKee  valve,  the  brake 
pipe  pressure  will  be  reduced  at  the  instant  of  placing  the 


208  BRAKE   VALVE    DEFECTS 

valve  on  running  position.  This  reduction  of  pressure  may 
apply  the  engine  brake;  as  soon  as  air  begins  to  pass  the 
excess  valve  the  brake  should  release. 

If  the  supplementary  reservoir  pipe  is  broken  or  leak- 
ing so  a  blind  joint  must  be  made  at  the  valve,  there  will 
be  so  little  air  in  chamber  D  that  the  equalizing  piston 
will  not  move  valve  110  to  graduate  and  stop  the  flow  of 
air  from  brake  pipe,  and  handle  123  must  be  moved  to 
lap  position  to  stop  the  discharge  of  brake  pipe  air. 

As  this  valve  has  two  sets  of  exhaust  ports,,  one  small 
for  the  service  application  and  a  large  port  for  the  emer- 
gency application,  the  work  of  reducing  the  brake  pipe 
pressure  is  very  easily  regulated. 


DEFECTS  OF  THE  BRAKE  VALVE 

If  air  leaks  past  main  slide  valve  into  brake  pipe,  it 
will  not  maintain  excess  pressure,  if  the  valve  is  in 
service  or  lap  position  during  an  application  of  the  brake 
this  leak  will  recharge  the  brake  pipe  and  release  the 
brake.  To  test  for  this  leak,  place  the  valve  on  lap,  close 
the  cut-off  cock  and  start  the  pump;  any  leak  into  the 
brake  pipe  will  be  shown  on  the  black  hand.  If  the  leak 
is  only  shown  when  the  valve  is  in  running  position,  the 
excess  pressure  valve  is  at  fault;  it  usually  only  needs 
cleaning.  While  doing  this  do  not  scratch  either  the  valve 
or  its  seat,  or  it  will  surely  leak  after  cleaning.  If  the 
cut-off  valve  110  leaks,  it  will  not  stop  the  flow  of  air 
from  the  brake  pipe  in  a  service  application ;  you  can  hear 
the  continuous  blow  at  the  exhaust  opening.  This  blow 
will  stop  if  you  move  the  valve  back  to  lap.  If  the  cut- 
out cock  is  closed,  the  black  hand  will  drop  to  zero,  unless 
there  is  a  leak  into  the  brake  pipe  cavity  A.  A  leak 
through  the  leather  gasket  under  the  cap  115-A  that 
allows  main  reservoir  air  to  get  into  port  O,  will  cause 
a  blow  at  the  exhaust  in  any  position  between  lap  and  full 
release.  In  any  other  position  it  will  charge  chamber  D 


BRAKE    VALVE    DEFECTS  209 

direct    from    the    main    reservoir.      The    openings    in    the 
gasket  at  O  should  be  the  exact  size  of  the  port  O. 

A  leak  from  the  supplementary  reservoir  or  its  con- 
nections, if  to  the  atmosphere,  is  easily  detected,  and 
should  be  remedied  if  the  automatic  closing  of  the  cut- 
off valve  110  is  to  be  satisfactory.  This  leak  will  reduce 
the  pressure  in  the  reservoir  so  the  piston  104  will  not 
move.  A  leak  from  chamber  D  back  into  the  brake  pipe 
can  be  detected  by  closing  the  cut-out  cock  under  the 
brake  valve,  placing  the  valve  in  emergency  for  an  instant 
to  empty  chamber  A  and  then  in  the  second  service  notch; 
a  leak  into  chamber  A  will  be  shown  on  the  black  hand. 
This  leak  may  be  past  the  leather  packing  ring  or  by  the 
ball  valve.  Before  making  this  test  be  sure  main  slide 
valve  does  not  leak  from  main  reservoir  into  brake  pipe. 
Lost  motion  between  handle  123  and  main  slide  valve  will 
allow  the  slide  valve  to  leave  the  ports  only  partially 
open;  this  will  affect  the  release  of  the  brake  very 
seriously.  This  affects  a  brake  pipe  reduction  when  made 
in  the  first  graduating  notch. 


THE   STRAIGHT  AIR   BRAKE 

The  Straight  Air  Brake  valve  shown  in  Figs.  1  and 
2,  has  a  slide  valve  227,  which  is  moved  by  the  lever  222 
with  its  lever  shaft  224,  and  slide  valve  lever  232.  When 
in  release  position,  Fig.  2,  the  port  b,  leading  from  the 
brake  cylinder  pipe  is  connected  with  the  exhaust  e  by  the 
cavity  c  of  the  slide  valve.  To  apply  the  brake  the  handle 
222  is  moved  to  application  position.  This  moves  valve 
227  so  as  to  lap  or  cover  the  exhaust  port  e  and  uncover 
port  b.  Main  reservoir  air,  which  has  been  reduced  to  45 
pounds  at  the  reducing  valve,  Fig.  3,  can  then  flow  from 
A  into  b  and  thence  to  the  double  check  valves  and  brake 
cylinders.  Gasket  121  prevents  leakage  of  air  along  the 
shaft  224.  The  reducing  valve  shown  in  Fig.  3  is  located 
between  the  main  reservoir  and  the  brake  valve.  The 
diaphram  complete  consists  of  the  stem  21,  the  washer 


210 


THE    STRAIGHT    AIR    BRAKE 


23  and  the  rubber  diaphram  32.  It  is  held  down  against 
the  air  pressure  in  B  by  the  regulating  spring  and  its  stem 
19.  As  long  as  the  pressure  in  B  is  less  than  the  regulat- 


THE    NEW   YORK   AIR    BRAKE   CO. 


Straight  Air  Engineer's  Valve, 


TO  MAIN  RESERVOIR 


ing  spring  is  adjusted  for,  which  is  45  pounds,  the  feed 
valve  26  is  held  off  its  seat.  When  this  pressure  reaches 
45  pounds,  the  spring  should  allow  the  diaphram  to  raise 
and  allow  feed  valve  26  to  seat,  thus  shutting  off  the 
flow  of  air  from  A  into  B. 

The  safety  valve,  Fig.   6,  has   a  release   lever  to  raise 
the  valve  off  its  seat  to  lower  the  brake  cylinder  pressure 


B-2     BRAKE     VALVE 


211 


when  necessary.  This  safety  valve  for  the  driver  brakes 
can  be  located  in  the  cab,  if  desired,  and  is  to  set  at  52 
pounds,  as  is  the  tender  brake  safety  valve. 

Safety  Valve   Fig. 
With  Release  Lever. 


Straight  Air 


Fig.  3 
Deducing  Valve, 


The  double  check  valve  used  is  shown  in  Fig.  4, 
question  38.  The  same  rules  apply  to  the  operation  of  this 
straight  air  brake  as  to  the  Westinghouse  equipments. 

The  B2  Brake  Valve  is  designed  to  operate  the  auto- 
matic brake  on  train  and  engine  in  the  same  manner  the 
1902  model  valve  does,  and  in  addition  apply  the  driver 
brake  with  straight  air,  this  does  away  with  a  separate 
straight  air  brake  valve.  It  also  operates  an  accelerator 
valve  that  passes  air  out  of  the  brake  pipe  to  the  atmos- 
phere during  a  service  application  on  a  long  train  and 
thus  makes  the  operation  of  the  triple  valves  more  pos- 
itive and  quicker.  There  is  a  duplex  controller  that  regu- 
lates the  supply  of  main  reservoir  air  to  the  brake  valve 


B-2    BRAKE    VALVE 


213 


by  reducing  it  to  brake  pipe  pressure  before  it  reaches 
the  brake  valve,  so  the  pressure  in  the  main  reservoir 
side  of  the  valve  will  not  rise  above  the  standard  desired 
in  the  brake  pipe,  this  does  away  with  the  excess  pressure 
attachment  used  with  the  1902  model.  The  arrangement 
of  this  equipment  is  shown  in  piping  diagram  on  this 
page. 

There  is  no  ball  check  valve  184  in  the  piston,  chamber 
D  being  charged  from  the  air  in  B  around  the  slide  valve 


tefe^g:^ 


through  a  small  port  W  in  the  valve  seat  leading  into 
passage  H  and  the  supplementary  reservoir.  Passage  O 
and  vent  valve  180  in  this  valve  serve  the  same  purpose  as 


214  OPERATION   OF    B-2   BRAKE  VALVE 

in  the  1902  model,  to  discharge  air  from  chamber  D  so 
that  brake  pipe  pressure  can  return  piston  193  to  its  normal 
position,  when  valve  180  closes  port  O. 

A  sectional  view  of  the  B2  valve  is  shown,  also  a  plan 
of  the  face  of  the  slide  valve  and  its  seat.  The  chief 
differences  between  this  valve  and  the  1902  model  are  the 
ports  in  the  slide  valve  and  the  seat.  Two  ports,  E  and 
V,  in  the  seat  are  connected  by  a  cored  passage  shown  by 
dotted  lines  through  the  valve  body  and  located  above 
passage  H,  into  this  passage  the  pipe  leading  to  the  brake 
cylinders  is  attached.  When  the  slide  valve  is  clear  ahead 
in  full  release  it  uncovers  port  E  so  air  from  the  top  of 
the  valve  in  B  can  pass  through  the  reducing  valve  set  at 
40  pounds,  to  the  brake  cylinders,  this  applies  the  engine 
brake  straight  air.  Air  from  B  passes  by  the  end  of  the 
slide  valve  and  also  through  ports  M  in  the  slide  valve 
into  the  brake  pipe  as  fast  as  the  air  can  pass  the  con- 
troller, releases  the  train  brake  and  charges  the  brake 
pipe  and  auxiliaries.  Port  T  in  the  seat,  leading  to  the 
accelerator  reservoir  is  open  through  J  in  the  slide  valve 
and  exhaust  C  to  the  atmosphere  and  port  O  is  the  same 
as  explained  with  the  1902  model.  Port  W  is  open  and 
keeps  chamber  D  equalized  with  B.  In  this  position  the 
train  brake  is  released  and  the  driver  brake  set  straight 
air. 

In  running  position  the  slide  valve  is  moved  back 
covering  port  E  so  no  more  air  passes  to  the  brake  cylin- 
der pipe,  port  V  in  the  seat  registers  with  R  in  the  valve 
so  brake  cylinder  air  can  exhaust  through  R,  J  and  C, 
this  releases  the  driver  brake.  Air  can  pass  to  the  brake 
pipe  through  the  large  ports  M  in  the  slide  valve  so  run- 
ning position  releases  both  the  train  and  driver  brakes. 
Ports  O  and  T  are  still  open  to  J  and  the  atmosphere. 
On  lap  all  ports  are  blanked  except  port  O,  this  is  left 
open  to  return  the  piston  and  graduating  valve  to  normal 
position,  if  a  service  reduction  has  been  made  so  the 
valve  will  graduate  at  the  next  reduction. 

In  the  graduating  positions,  ports  F  and  G  are  opened 


OPERATION  OF  B-2  BRAKE  VALVE  215 

by  a  movement  of  the  slide  valve  and  port  F  closed  by 
the  graduating  valve  as  with  the  1902  model.  But  as  port 
S  in  the  valve  is  opened  at  the  same  time  with  port  F, 
when  air  is  flowing  from  F  into  G,  it  is  also  flowing 
through  S,  the  passage  X  and  into  the  opening  Ac  that  is 
connected  by  port  T  in  the  seat  and  Y  to  the  accelerator 
reservoir.  As  soon  as  the  proper  brake  pipe  reduction 
for  that  notch  is  made  valve  110  will  close  ports  S  and  F. 
A  movement  of  the  handle  to  the  next  notch  will  open 
ports  S  and  F  again  and  valve  110  will  close  them; 
brake  pipe  air  flows  to  the  accelerator  valve  chamber  at 
the  same  time  it  flows  through  F  and  G  and  exhaust  C. 
When  the  last  graduating  position  is  reached  the  restricted 
passage  N  in  the  end  of  the  slide  valve  has  been  moved 
over  port  V  so  air  begins  to  flow  from  the  brake  valve  to 
the  brake  cylinder.  As  the  engine  triple  valve  has  been 
sending  air  to  the  cylinders  during  the  service  application 
the  supply  of  air  through  port  V  tends  to  maintain  the 
pressure  during  a  full  application.  The  action  of  the 
valve  in  emergency  is  exactly  like  that  of  the  1902  valve 
before  described.  The  reducing  valve  used  with  this 
equipment  is  the  same  one  described  in  connection  with 
the  Straight  Air  Brake. 


83   BRAKE  VALVE 

This  valve  in  some  respects  is  similar  to  the  B2  just 
described.  The  engine  and  tender  brake  have  triple 
valves  for  automatic  service  and  double  check  valves  to 
enable  straight  air  to  be  used,  which  can  be  applied  in 
full  release  or  emergency  positions  releasing  it  in  run- 
ning position  whether  applied  with  straight  air  or  auto- 
matically, with  this  valve  the  main  reservoir  pressure  is 
reduced  to  40  pounds  before  reaching  the  brake  valve  for 
use  in  straight  air  applications.  It  operates  the  acceler- 
ator valve  in  the  same  manner  as  the  B2,  using  the  same 
design  of  divided  reservoir. 

The  piping   diagram   of   the    B3    when   compared   with 


OPERATION  OF  B-3   BRAKE  VALVE 


217 


the  B2  will  show  some  of  the  differences.  A  sectional 
view  of  the  complete  valve,  also  a  plan  of  the  slide  valve 
and  its  seat  is  shown  so  the  differences  between  the  ports 
and  cavities  in  the  B2  and  B3  are  plain.  The  valve  cover 
is  fastened  to  the  body  by  tap  bolts  instead  of  screws; 
port  o  is  cored  through  the  body  instead  of  being  drilled 
through  the  cover,  it  does  not  show  in  the  sectional  side 
elevation.  The  plan  of  the  valve  seat  and  body  shows  a 
pipe  bracket  bolted  to  the  side,  dotted  lines  show  the 
cored  passages  to  port  N  and  from  port  E  through  which 
air  passes  on  its  way  to  the  brake  cylinders  in  a  straight 


ake  Valve. 


-. 

air  application.     V  is  the  straight  air  exhaust  port;  C  is 
the   brake    pipe    exhaust    port;    o    is    the    discharge    port 


218  OPERATION   OF   B-3   BRAKE  VALVE 

through  which  the  air  from  behind  piston  311  can  pass 
out  in  full  release,  running  and  lap  positions;  T  is  the 
port  leading  to  the  accelerator  reservoir;  W  leads  to  the 
supplementary  reservoir  and  chamber  D  behind  piston 
311;  A  is  the  opening  through  which  main  reservoir  air 
that  enters  at  B  can  pass  into  the  brake  pipe  in  release 
and  running  positions.  On  the  plan  of  the  face  of  the 
slide  valve,  M-M  are  two  openings  in  the.  end  of  the 
valve  through  which  this  air  passes  in  release  and  run- 
ning positions  as  well  as  passing  by  the  end  of  the  valve 
in  full  release;  port  F  is  connected  to  G  by  a  passage 
through  the  body  of  the  valve  312,  better  shown  in  the 
side  elevation  and  used  in  service  application  to  pass  air 
from  A  to  C;  ports  J-J  are  likewise  connected  with  K 
and  large  enough  to  make  the  emergency  reduction  from 
A  to  C ;  groove  P  in  the  face  of  the  valve  serves  to  charge 
chamber  D  and  supplementary  reservoir  through  port  W 
in  release  and  running  positions;  ports  L-L  are  connected 
by  a  cavity  in  valve  312,  they  register  with  ports  N  and 
E  for  the  straight  air  application  in  full  release;  cavity 
R  connects  E  and  V  in  running  position  to  release  the 
straight  air  brake,  and  to  discharge  air  from  port  o  in 
release,  running  and  lap  position.  Port  S  connects  with 
cavity  through  Ac,  a  passage  shown  by  dotted  lines;  cavity 
Ac  is  over  port  T  leading  to  the  accelerator  reservoir  in 
the  graduating  positions  so  that  some  of  the  brake  pipe 
air  escaping,  during  a  service  reduction  can  flow  to  the 
accelerator  reservoir  and  build  up  a  pressure  there  to 
operate  the  accelerator  valve;  port  T  is  open  to  J  in 
running  position  so  air  can  all  escape  from  the  acceler- 
ator reservoir. 

Main  reservoir  air  reduced  to  the  standard  brake  pipe 
pressure  at  the  duplex  controller  comes  into  the  brake 
valve  at  B  and  is  around  the  slide  valve,  in  automatic-re- 
lease and  straight-air-application  position  air  flows  through 
ports  M  and  by  the  end  of  valve  312  into  the  brake  pipe 
and  equalize  there  with  B.  Main  reservoir  air  also  passes 
the  single  pressure  controller  set  at  40  pounds  into  port 


OPERATION  OF  B-3   BRAKE  VALVE  219 

N  then  through  port  E,  the  double  check  and  into  brake 
cylinder.  Port  o  is  open  to  cavity  R  and  port  V  so  air 
behind  piston  311  is  discharged  to  allow  brake  pipe  air  to 
force  the  piston  to  normal  position,  when  in  normal 
position  valve  180  closes  port  o  at  that  end  and  no  more 
air  can  pass  through  o,  the  supplementary  reservoir  will 
then  charge  through  port  W;  port  T  is  open  through  J 
and  C.  Placing  the  brake  valves  midway  between  release 
and  running  position  will  lap  the  straight  air  ports  N  and 
E  so  no  air  can  pass  in  or  out  of  the  brake  cylinders^ 
through  the  brake  valve  and  will  hold  the  engine  brakes 
partially  applied. 

Running  position  will  release  both  automatic  and 
straight  air  brakes,  the  straight  air  will  come  back  through 
port  E  and  passing  into  cavity  R  will  escape  through  V 
into  C.  In  lap  position  all  ports  are  closed,  except  o, 
this  open  port  is  to  return  piston  311  to  normal  position 
in  case  it  has  been  moved  in  a  service  application  and 
the  brake  valve  moved  to  lap.  There  are  five  service  or 
graduating  positions,  each  having  a  notch  in  the  quadrant, 
they  are  calculated  to  make  automatic  reductions  from  70 
pounds  brake  pipe  pressure  of  5,  8,  11,  15  and  23  pounds, 
or  in  that  proportion  for  any  higher  pressure.  In  any 
service  reduction,  ports  F  and  S  in  the  face  of  valve  312 
are  open,  F  to  the  atmosphere  through  G;  S  to  Ac  and 
the  accelerator  reservoir  till  the  brake  pipe  reduction  is 
sufficient  to  allow  air  in  chamber  D  to  move  piston  311 
and  cut-off  valve  317  to  close  them.  In  the  last  graduating 
notch  cavity  R  opens  to  port  N  a  very  little  so  main 
reservoir  air  can  flow  from  N  to  E,  into  the  double  check 
and  cylinders  and  reinforce  the  automatic  application  if 
it  has  leaked  below  40  pounds. 

In  the  emergency  position  ports  J  and  K  allow  the 
brake  pipe  air  to  flash  out  to  the  atmosphere,  this  sudden 
reduction  of  brake  pipe  pressure  operates  all  triples  as 
quickly  as  possible.  The  straight  air  is  also  set  full  on 
through  ports  N  and  E  in  case  the  triple  valves  does  not 
make  the  cylinder  pressure  on  the  engine  above  40  pounds. 


220 


DUPLEX     CONTROLLER 


The  reducing  valve  for  the  straight  air  brake  is  a 
94-inch  single  controller,  the  regulating  top  is  connected 
with  a  small  pipe  with  the  pipe  leading  from  the  B3 
valve  to  the  double  check,  so  the  controller  operates  to 
close  off  when  the  pressure  builds  up  in  this  pipe  to  40 
pounds.  With  no  air  in  this  pipe  the  controller  is  open 
and  main  reservoir  air  comes  as  far  as  port  N  without 
any  reduction.  In  all  other  respects  the  equipment  of 
divided  reservoir,  accelerator  valve,  safety  valve  and  high 
speed  controller  is  the  same  as  with  B2. 


DUPLEX    CONTROLLER. 


THE    DUPLEX   CONTROLLER 

This  valve  is  located  between  the  main  reservoir  and 
the  brake  valve;  its  duty  is  to  reduce  the  main  reservoir 
pressure  to  that  required  in  the  brake  pipe  before  reach- 
ing the  brake  valve.  There  are  two  forms  of  it  in  service, 
only  the  latest  form  of  it  is  here  illustrated.  In  its  con- 
struction it  is  like  the  duplex  pump  governor,  except  that 
its  valve  has  a  leather  seat.  The  regulating  tops  can 
be  located  in  the  cab  and  connected  to  the  controller  body 
by  a  copper  pipe.  One  of  the  tops  is  adjusted  for  the 
ordinary  brake  pipe  pressure,  the  other  for  the  higher 
pressure  used  with  the  High  Speed  Brake.  When  one 
side  is*  cut  in  by  the  union  three-way  cock  the  other  is 
cut  out,  either  one  of  the  two  pressures  can  be  carried  in 
the  brake  valve  and  brake  pipe.  The  description  of  the 
duplex  pump  governor  and  its  operation  will  be  sufficient 
to  show  how  the  controller  operates.  Air  enters  at  the 
opening  marked  MR,  if  the  controller  valve  is  open  it 
can  pass  through  and  out  to  the  brake  valve  at  BV. 
When  necessary  in  steep  grade  work  to  have  full  main 
reservoir  pressure  in  the  brake  valve  the  controller  valve 
can  be  held  open  by  screwing  the  hand  wheel  up  the  full 
travel  of  its  screw. 


THE   ACCELERATOR  VALVE 

This  valve  is  intended  to  discharge  brake  pipe  air 
during  a  service  reduction  in  addition  to  that  taken  out 
by  the  brake  valve.  It  has  a  divided  reservoir;  one  side 
for  the  accelerator  valve  to  which  the  valve  is  bolted,  the 
other  is  the  supplementary  reservoir  for  the  brake  valve. 
When  air  from  the  brake  valve  during  a  service  reduction 
passes  through  ports  S  and  T  to  the  reservoir  it  also 
comes  through  port  Q  over  piston  65.  With  a  short  train, 
less  than  ten  cars,  port  S  is  closed  by  the  graduating 
valve  before  sufficient  air  has  passed  into  the  accelerator 
chamber  to  operate  its  valve.  With  a  train  of  over  ten 


222 


OPERATION    OF    ACCELERATOR    VALVE 


cars  the  pressure  in  the  chamber  will  build  up  till  it  is 
sufficient  to  force  piston  65  and  with  it  stem  67  and  valve 
74  down  against  the  tension  of  spring  31  in  the  bottom 
of  the  valve.  In  valve  74  is  an  oblong  port  a  and  in  the 
seat  a  A  shaped  port  b.  When  valve  74  is  moved  down 
port  a  first  opens  to  the  pointed  end  of  port  b,  and  brake 
pipe  air  coming  in  at  the  opening  TP  begins  to  flow  out  of 
b  slowly.  As  the  valve  74  is  moved  farther  down  by  the 
increasing  pressure  of  the  air  above  piston  65,  ports  a  and 
•b  are  opened  wider  till  their  full  opening  is  made;  this 
gives  a  gradual  discharge  of  brake  pipe  air  that  with  a 
long  train  begins  about  four  seconds  after  the  brake  valve 
begins  discharging  air.  It  requires  15  to  17  pounds  press- 
ure in  the  chamber  to  operate  the  valve.  Through  piston 
65  is  a  small  port  S  through  which  air  that  comes  over 
the  piston  can  discharge  into  the  space  under  the  piston 
and  then  to  the  atmosphere  through  port  T ;  air  flows  out 
here  at  the  same  time  it  comes  into  the  reservoir  and 
prevents  any  sudden  rise  of  pressure  in  the  reservoir. 


When  piston  65  moves  down  it  uncovers  port  R  in  the 
bushing,  this  also  takes  air  out  of  the  reservoir.  As  soon 
as  the  graduating  valve  laps  port  S  in  the  brake  valve, 


THE     HIGH     SPEED    CONTROLLER 


223 


no  more  brake  pipe  air  will  flow  to  the  chamber;  ports 
3  and  R  in  the  accelerator  piston  will  then  gradually  re- 
duce the  pressure  in  the  chamber  and  allow  spring  31  to 
move  valve  74  and  piston  65  up,  gradually  closing  ports 
a  and  b.  When  piston  65  closes  port  R  the  flow  of  air 
out  of  S  alone  is  so  much  slower  that  piston  65  gives  a 
very  slow  closure  to  port  b.  The  gasket  70  makes  a  tight 
joint  on  its  seat  around  stem  67  when  the  valve  is  closed, 
so  brake  pipe  air  cannot  escape  around  the  stem. 


THE   HIGH   SPEED   CONTROLLER 

The  Jiigh  speed  controller  connects  with  the  brake 
cylinder  pipe  at  BC  and  to  the  brake  pipe  at  BP,  so  that 
brake  pipe  air  pressure  is  always  in  the  body  of  the  valve 
and  when  greater  than  brake  cylinder  pressure  will  hold 


SI09 


piston  107  in  normal  position  as  shown,  leather  gaskets 
are  on  each  side  of  the  piston  to  make  the  joint  tight.  A 
moderately  large  opening  around  the  valve  108  allows  air 
from  the  cylinder  to  reach  the  safety  valve  freely  and 


224  THE     AUTOMATIC     CONTROL 

rapidly  reduce  any  excess  of  pressure  above  that  the 
safety  valve  is  set  for,  this  takes  place  in  a  service  applica- 
tion. In  an  emergency  application  the  brake  pipe  pressure 
is  suddenly  reduced  below  what  the  brake  cylinder  can 
build  up  to,  and  piston  107  will  move  over  to  the  right 
with  the  leather  gasket  resting  against  the  seat  C.  This 
brings  the  small  valve  108  under  passage  G  so  the  cylinder 
air  blows  down  gradually  in  this  position  till  the  limit 
for  which  the  safety  valve  is  adjusted  is  reached,  this 
should  be  53  pounds.  Ports  D  and  F  are  to  allow  cylinder 
air  quick  access  to  the  ends  of  the  valve  108  and  piston 
107  so  they  will  move  with  a  low  difference  of  pressures 
on  piston  107. 

The  Automatic  Control  equipment  of  the  New  York 
Brake  Co.  is  for  locomotive  service,  either  with  or  with- 
out the  train  brakes.  The  piping  diagram  shows  the 
various  parts,  the  automatic  brake  valve;  double  pressure 
feed  valve;  reducing  valve;  pump  governor;  strainer 
check  valve  and  safety  valve  are  the  same  in  construction 
and  operation  as  those  described  in  answer  to  questions 
35-37,  so  they  need  not  be  described  again  here.  The 
straight  air  brake  valve  and  double  throw  check  valve 
have  been  described  in  the  New  York  equipment  a  few 
pages  previous.  The  straight  air  brake  valve  is  used  to 
pass  air  directly  to  and  from  the  locomotive  brake  cylin- 
ders, it  does  not  send  any  air  to  the  Automatic  Control 
valve  as  the  independent  brake  valve  does  to  the  distrib- 
uting valve  in  the  ET  equipment.  The  double  throw 
check  valve  is  located  in  the  pipe  line  between  the  brake 
cylinders  and  the  straight  air  brake  valve  on  one  side  and 
the  Automatic  Control  valve  on  the  other  side;  the  duty 
of  this  double  throw  check  is  to  close  the  exhaust  to  the 
straight  air  valve  when  the  control  valve  is  operated  and 
vice  versa.  A  safety  valve  is  attached  to  the  control 
valve  and  a  release  valve  or  bleeder  to  the  retaining 
pipe  between  the  control  valve  and  the  automatic  brake 
valve.  Stop  cocks  are  located  in  the  various  pipes  to  cut 
out  the  air  when  necessary  and  choke  fittings  near  the 


226 


AUTOMATIC    CONTROL    VALVE 


hose  .connections  leading  to  the  tender  brake  and  engine 
truck  brake  to  hold  tKe  air  back  in  case  either  of  these 
hose  burst  or  come  uncoupled.  The  double  chambered 
reservoir  is  the  same  as  shown  with  the  ET  equipment. 


Automatic  Control  Valve 


The  Automatic  Control  valve  is  shown  in  two  sectional 
views,  the  view  at  the  right  shows  the  passages  to  the 
double  chambered  reservoir,  the  left  one  a  sectional  view 
from  in  front.  On  another  page  is  shown  a  diagrammatic 
view,  as  the  air  ports  and  valves  cannot  be  shown  in  a 
correct  sectional  view.  This  cut  shows  the  double 
chambered  reservoir  attached  at  the  bottom  of  the  valve, 
the  reservoirs  are  of  such  a  relative  size  that  they  will 
equalize  at  50  from  70  pounds  in  the  auxiliary. 

The  valve  is  in  full  release  position,  triple  valve  piston 
3  is  at  the  bottom  of  its  cylinder  so  feed  port  at  G  is 
open,  slide  valve  4  and  graduating  valve  10  are  in  normal 
position  to  exhaust  air  from  the  control  reservoir  and 
chamber  D  above  control  piston  2.  Control  piston  2  is 
at  the  upper  end  of  its  cylinder  in  normal  or  release 
position,  by  it  exhaust  valve  7  is  held  open  so  brake 
cylinder  air  coming  in  at  C  can  escape  at  exhaust  N. 
Main  reservoir  air  comes  in  at  A  at  full  pressure  around 
admission  valve  1,  spring  8  holds  this  valve  on  its  seat 
when  ther'e  is  no  air  pressure  to  do  it.  Brake  pipe  air 


FULL   RELEASE 


TO  LEVER  RELEASE 


TO  BRAKE  VALVE 

Automatic  Control  Valve, 


228  OPERATION    OF    AUTOMATIC    CONTROL    VALVE 

comes  in  over  piston  3  at  BP;  at  IV  is  the  exhaust 
through  the  control  cylinder  release  pipe  connected  to  the 
automatic  brake  valve;  the  control  reservoir  pipe  is  at  II 
and  the  continuous  feed  pipe  from  the  reducing  valve 
pipe  of  the  straight  air  valve  to  the  auxiliary  reservoir 
is  at  VI.  The  safety  valve  is  attached  to  port  L  and  will 
blow  down  the  pressure  in  the  control  reservoir  to 
standard  with  either  a  full  service  or  emergency  applica- 
tion; with  the  triple  valve  on  lap  the  safety  valve  is  cut 
out. 

To  operate  this  valve  after  the  auxiliary  reservoir  is 
charged  to  standard  pressure  from  the  brake  pipe,  a  brake 
pipe  reduction  is  made.  Piston  3  at  once  moves  up*  follow- 
ing the  reduction  in  F  carrying  with  it  graduating  valve 
10  and  slide  valve  4;  closing  feed  groove  G;  moving  valve 
10  to  uncover  port  J  in  slide  valve  4,  which  is  moved 
up  so  port  j  registers  with  E  in  the  seat,  also  lapping 
exhaust  port  M.  Air  from  the  auxiliary  reservoir  now 
flows  into  the  control  reservoir  and  D  over  control  piston 
2  building  up  a  pressure  in  both  places.  When  the  press- 
ure in  the  auxiliary  is  a  little  less  than  that  of  the  brake 
pipe,  piston  3  will  move  down  carrying  valve  10  with  it 
and  lap  port  J  so  no  more  air  can  go  into  D  and  the 
control  reservoir.  Pressure  on  piston  2  will  move  it 
down  carrying  valve  7  down  over  exhaust  port  N,  a 
farther  movement  will  push  preliminary  admission  valve 
Al  off  its  seat  in  admission  valve  1,  this  allows  air  in  O 
to  flow  out  into  B;  as  air  cannot  get  by  the  guide  case 
or  extension  of  1  as  fast  as  it  gets  out,  this  tends  to 
balance  valve  1  so  piston  2  can  open  it  easily.  Main 
reservoir  air  then  flows  into  B  and  the  brake  cylinders 
till  the  pressures  there  are  a  little  above  that  in  D  and 
the  control  reservoir,  piston  2  then  moves  up  and  allows 
valves  1  and  Al  to  close,  but  does  not  open  exhaust 
valve  7,  this  holds  the  engine  brakes  applied  automatically. 
If,  on  account  of  leaks,  the  brake  cylinder  pressure  drops, 
it  will  be  less  than  in  D,  piston  2  will  at  once  open  the 
admission  valve  and  raise  the  cylinder  pressure  and  in 


OPERATION    OF    AUTOMATIC    CONTROL    VALVE  229 

B  till  it  can  push  piston  2  up  so  admission  valve  can 
just  supply  the  leak.  For  a  full  application  the  brake 
pipe  pressure  is  reduced  20  pounds  from  70,  this  will 
hold  triple  piston  up  and  slide  valve  ports  open,  equalizing 
the  auxiliary  and  control  reservoirs. 

If,  on  a  full  application  the  pressure  in  the  control 
reservoir  exceeds  the  adjustment  of  the  safety  valve,  it 
will  blow  down,  the  brake  cylinder  pressure  will  not  build 
up  any  higher  than  that  in  D.  Air  from  the  control 
reservoir  can  flow  to  the  safety  valve  from  port  E 
through  U,  cavity  V  in  valve  10  and  port  W  into  L. 

When  an  emergency  application  is  made,  piston  3  and 
its  valves  make  a  full  travel  at  once,  valve  4  uncovers  port 
E  so  auxiliary  air  can  flow  quickly  into  D  forcing  control 
piston  2  down,  operating  its  valves  in  short  order.  Port 
P  in  the  slide  valve  now  registers  with  port  L  so  air 
from  the  auxiliary  and  control  reservoirs  can  get  to  the 
safety  valve.  A  small  port  in  the  automatic  brake  valve 
(if  the  rotary  is  in  emergency  position),  will  send  a 
supply  of  main  reservoir  air  through  the  pipe  marked  CR 
on  the  piping  diagram  into  the  control  reservoir  at  II, 
this  will  hold  the  pressure  there  up  to  where  port  P  can 
handle  it  all  to  the  safety  valve,  thus  giving  a  higher 
braking  pressure  in  the  emergency  than  in  a  service  ap- 
plication. 

A  quick-action  cylinder  cap  for  the  triple  valve  can 
be  furnished  if  desired  that  will  vent  some  of  the  brake 
pipe  air  to  chamber  B  below  control  piston,  this  will 
operate  the  car  triples  quicker  than  when  the  reduction 
is  made  at  the  brake  valve  only. 

To  automatically  maintain  the  pressure  in  the  auxiliary 
reservoir  there  is  a  pipe  connected  at  VI  that  leads  from 
the  reduced  pressure  pipe  between  the  reducing  valve  and 
the  straight  air  brake  valve,  on  the  diagram  this  is 
marked  PC.  If  from  any  cause  the  pressure  in  the 
auxiliary  drops  below  the  adjustment  of  the  reducing 
valve  (which  should  be  set  at  45  pounds),  air  can  flow 
into  the  auxiliary  and  set  the  brake  through  the  control 


230 


STRAINER     CHECK    VALVE 


valve  up  to  that  pressure.  To  do  this  it  moves  the  triple 
piston  up  against  the  depleted  brake  pipe  pressure  and 
passes  into  D,  thus  operating  piston  2.  There  is  a 
strainer  check  valve  in  pipe  PC  to  prevent  air  at  over 
45  pounds  getting  back  into  the  reduced  pressure  pipe 
and  a  stop  cock  to  cut  out  the  air  in  case  the  reducing 
valve  gets  out  of  order  or  the  brake  pipe  is  cut  out.  If 
at  any  time  the  pressure  in  the  reduced  pressure  pipe 

Strainer  and  Check  Valve. 

^DC  93        /DC  92 

>CI2I 
DC  1 22 


exceeds  that  in  the  brake  pipe  the  engine  brake  will  set 
and  stay  set. 

To  operate  the  locomotive  brake  automatically  leave 
the  straight  air  brake  on  release  position  and  make  the 
proper  brake  pipe  reduction  with  the  automatic  brake 
valve.  When  releasing  avoid  overcharging  the  engine 
auxiliary  by  leaving  the  brake  valve  on  full  release  too 
long  as  when  you  go  to  running  position  the  drop  in 
brake  pipe  pressure  may  set  the  engine  brake.  If  the 
engine  brake  is  to  be  held  set  and  the  train  brake  released 
go  to  full  release  and  stay  there  a  few  seconds  till  all 
triples  release,  then  go  to  holding  position,  this  will 
not  overcharge  the  brake  pipe  and  will  hold  the  locomotive 
brakes  set,  because  air  from  control  reservoir  cannot 
escape  after  its  triple  goes  to  release  till  the  brake  valve 
is  put  in  running  position.  When  the  straight  air  brake 
is  used  leave  the  automatic  brake  valve  on  running  posi- 
tion and  apply  and  release  the  engine  brake  with  the 
straight  air  valve.  To  release  the  engine  brake  after  it 
is  set  automatically  without  releasing  the  train  brake  also, 


QUICK     ACTION     TRIPLE    VALVE  231 

use  the  hand  release  valve  or  bleeder  that  is  connected  to 
control  reservoir  by  pipe  CR ;  by  bleeding  this  reservoir 
piston  2  will  be  moved  to  open  exhaust  valve  7.  The 
straight  air  brake  valve  will  not  release  the  engine  brake 
when  set  automatically,  the  double  throw  check  valve 
will  prevent  it. 

At  any  time  when  set  automatically  the  engine  brake 
can  be  released  by  holding  the  bleeder  open,  but  it  has 
no  effect  when  set  by  straight  air  as  the  double  check 
valve  will  close  the  opening  from  the  cylinders  to  the 
control  valve. 


THE  QUICK  ACTION  TRIPLE  VALVE 

The  Quick  Action  Triple  Valve  is  used  on  passenger 
and  freight  cars  and  some  passenger  tenders.  The  one 
shown  in  section  is  the  older  type  of  freight  car  triple. 
The  passenger  triple  valve  for  12,  14  and  16-inch  brake 
cylinders  has  the  graduating  valve  48  located  on  top  of 
slide  valve  38,  and  the  service  port  through  valve  38  as 
well  as  in  its  seat,  the  vent  valve  piston  has  the  port 
F  through  the  stem  129.  The  new  type  of  freight  triple 
also  has  the  vent  valve  piston  made  like  the  passenger 
triple.  These  triples  are  shown  in  Plate  R-24. 

As  some  of  the  moving  parts  are  at  right  angles  to 
each  other,  this  cut  does  not  show  them  as  clearly  as  the 
diagrammatic  views.  The  same  reference  numbers  and 
letters  are  used  in  both  illustrations.  Referring  to  page 
196,  the  triple  valve  body  125  contains  the  two  bushings 
in  which  main  piston  128  and  the  valves  38  and  48  move; 
126  is  the  front  cap  which  contains  vent  valve  71  and  its 
spring  132;  it  also  holds  the  stem  of  129  in  position.  The 
vent  valve  seat  or  "middle  section"  130  makes  the  cap 
for  the  cylinder  of  the  triple  piston  128.  127  is  the  side 
cap  and  covers  the  quick-action  valve  piston  137.  Main 
piston  128  is  extended  so  that  it  forms  a  cylinder  in 
which  another  piston,  129,  is  fitted,  the  stem  of  which 
passes  through  130  and  is  held  from  moving  to  the  right 


OPERATION    OF    QUICK    ACTION     TRIPLE  233 

by  a  clip  or  piston  stop  142,  so  that  when  piston  128 
moves  to  release  position  vent  valve  piston  is  in  its  normal 
position,  and  a  chamber,  G,  is  left  between  the  two 
pistons.  A  small  port  F  through  piston  129  allows  brake 
pipe  air  to  pass  in  and  out  of  chamber  G.  This  port  is 
of  such  a  size  that  when  piston  128  moves  slowly  to  the 
left  in  a  service  application,  tlie  air  in  G  can  pass  out 
to  the  brake  pipe  side  of  piston  129,  and  piston  129  will 
remain  stationary  with  regard  to  130  and  vent  valve  71, 
as  shown  in  service  position.  This  vent  valve  is  held  on 
its  seat  by  the  pressure  of  the  brake  pipe  air  and 
spring  132. 

In  a  graduated  service  application  when  the  brake  pipe 
pressure  is  reduced  in  A  the  auxiliary  pressure  in  the 
auxiliary  side  moves  piston  .128  towards  the  decreasing 
brake  pipe  pressure,  first  closing  the  feed  port  B  and 
moving  graduating  valve  48  with  the  piston.  As  soon  as 
the  lost  motion  between  the  piston  shoulders  and  exhaust 
valve  38  is  taken  up  valve  38  moves  and  closes  the  exhaust 
port  so  no  brake  cylinder  air  can  escape  to  the  atmosphere. 
The  port  to  the  brake  cylinder  under  valve  48  is  next 
opened,  and  air  from  the  auxiliary  flows  to  the  cylinder, 
applying  the  brake.  When  the  flow  of  brake  pipe  air  out 
of  the  brake  valve  stops,  the  reduction  in  A  also  stops, 
and  as  valve  48  is  still  open  the  auxiliary  pressure  soon 
gets  lower  than  that  of  the  brake  pipe  so  piston  128  is 
moved  to  the  right  and  closes  valve  48,  but  does  not  move 
valve  38;  this  holds  the  brake  set.  Another  brake  pipe 
reduction  produces  the  same  movements  of  the  piston  and 
valves  and  so  on  till  the  brake  pipe  reductions  make  the 
pressure  lower  than  that  of  the  auxiliary,  when  the 
piston  will  not  move  back  to  close  the  graduating  valve 
48.  To  release  the  brake  the  brake  pipe  pressure  is  raised 
higher  than  the  auxiliary,  this  moves  piston  128  and  valves 
38  and  48  to  release  position,  covering  the  service  port 
and  opening  the  exhaust  port. 

The  triple  piston  128  makes  a  full  stroke  in  either 
service  or  emergency  application,  the  edge  of  cylinder  128 


EMERGENCY    APPLICATION  235 

striking  the  leather  gasket  133,  so  that  no  graduating 
spring  is  used  to  assist  in  stopping  the  triple  piston  in  the 
service  position,  and  the  piston  does  not  get  any  assistance 
from  a  graduating  spring  when  starting  from  emergency 
or  full  stroke  towards  release  position. 

If  the  reduction  in  brake  pipe  pressure  is  made  so 
suddenly  that  the  air  in  chamber  G  can  not  pass  through 
port  F  fast  enough  to  equalize  with  the  brake  pipe  reduc- 
tion, the  pressure  of  air  in  G  will  move  piston  129  over  at 
the  same  time  piston  128  moves.  The  stem  of  129  will 
push  vent  valve  71  away  from  its  seat,  as  shown  in  the 
emergency  application;  brake  pipe  air  from  the  chamber 
around  valve  71  can  flow  rapidly  into  passage  H,  and 
thence  against  the  quick-action  piston  137.  This  in  its 
turn  is  moved  to  the  right  by  the  pressure  of  brake  pipe 
air  and  quick-action  valve  138  is  unseated,  opening  a  large 
passage  for  auxiliary  air  to  flow  through  K  into  L — L, 
forcing  check  valve  117  off  its  seat ;  the  air  also  passes  into 
the  brake  cylinder  through  the  usual  opening  at  the  grad- 
uating valve.  No  air  from  the  brake  pipe  reaches  the 
brake  cylinder,  only  that  from  the  auxiliary,  but  the 
auxiliary  air  passes  through  such  large  ports  K  and  L 
that  the  equalization  between  the  auxiliary  and  cylinder 
is  almost  instantaneous  after  valve  138  is  opened.  As 
soon  as  these  pressures  have  equalized,  check  valve  117 
closes  and  prevents  brake  cylinder  air  flowing  back  into 
L  and  thence  around  the  stem  of  piston  137  to  the  atmos- 
phere. In  the  meantime  air  in  chamber  G  has  equalized 
through  port  F  so  that  spring  132  can  push  vent  valve  71 
and  piston  129  to  their  normal  positions.  When  vent  valve 
71  seats,  no  more  air  flows  from  brake  pipe  to  passage 
H ;  air  escaping  from  ports  M  and  J  at  once  reduces  the 
pressure  on  piston  137,  which  is  moved  to  the  left,  its 
normal  position,  by  the  stiffness  of  spring  140.  Valve 
138  is  closed  and  no  more  air  can  pass  from  the  auxiliary 
into  L,  and  all  the  quick-action  parts  of  the  triple  valve 
are  returned  to  their  normal  positions.  Pistdn  128  having 
made  a  full  stroke,  valve  48  is  open  so  that  auxiliary  air 


236  EMERGENCY    APPLICATION 

can  pass  into  the  brake  cylinder  and  keep  the  pressures 
equalized.  With  70  pounds  auxiliary  pressure  and  the 
standard  piston  travel  the  equalization  is  the  same  for 
full  service  and  emergency  applications,  50  pounds  per  inch. 

Venting  the  brake  pipe  air  to  the  atmosphere  past  valve 
71  and  through  ports  M  and  J,  should  reduce  its  pressure 
below  that  in  the  auxiliary;  this  will  hold  piston  128  in 
service  position. 

The  sudden  venting  of  brake  pipe  air  to  the  atmosphere 
at  this  triple  makes  a  sudden  reduction  at  the  next  triple, 
which  in  turn  operates  quick-action,  and  so  on  from  one 
triple  to  another  to  the  end  of  the  train;  this  is  called  the 
"serial"  action. 

If  there  are,  close  to  the  head  end  of  the  train,  several 
triple  valves  cut  out,  or  defective  triples  that  do  not  oper- 
ate the  vent  valve  so  as  to  vent  enough  air  from  the  brake 
pipe,  or  cars  with  brake  pipe  only,  the  sudden  reduction 
may  not  extend  far  enough  to  affect  a  quick-action  triple 
so  it  works  quick-action  and  continues  the  sudden  serial 
reduction.  About  three  "cut-out"  triples  next  the  engine 
is  the  limit  to  have  the  quick-action  "jump  over."  At  the 
rear  end  of  the  train  the  quick-action  will  jump  more 
than  three  cars,  because  the  volume  of  brake  pipe  air 
behind  these  defective  triples  is  less  than  when  they  are 
near  to  the  head  end  of  the  train. 

This  type  of  triple  valve  does  not  send  any  brake  pipe 
air  to  the  brake  cylinder;  the  brake  cylinder  pressure  is 
the  same  with  either  a  full  service  or  an  emergency  appli- 
cation; so  that  the  same  increase  of  brake  pipe  pressure  is 
required  to  move  the  triple  valve  to  release  position. 
When  brake  pipe  pressure  is  restored  so  that  it  is  greater 
than  auxiliary  pressure,  or  the  auxiliary  pressure  has 
leaked  down,  or  been  bled  out,  brake  pipe  air  passing 
through  port  F  into  chamber  G  moves  piston  128  and 
valves  38  and  48  to  release  position;  this  closes  the  service 
port,  opens  the  exhaust  port  to  release  the  air  from  the 
brake  cylinder,  and  opens  feed  port  B  to  recharge  the 
auxiliary. 


IMPROVED    QUICK    ACTION    TRIPLB    VALVR. 

FOR  it  AND  14  INCH  PASSSNGHR  CYLINDERS. 

PLATE   R  24. 


238  TRIPLE    VALVE    OPERATIONS 

If  the  piston  128  is  in  lap  position,  the  volume  of  air 
in  chamber  G  is  so  small  that  in  an  emergency  reduction 
of  brake  pipe  air,  the  pressures  can  equalize  through  port 
F  and  piston  129  will  rarely  move.  If  piston  128  is  in 
service  position,  it  is  at  the  end  of  its  travel  and  can  not 
move  any  further.  Therefore,  after  pistons  128  in  the 
triples  have  responded  to  a  service  reduction,  no  matter 
how  light,  the  quick-action  parts  of  these  triples  will  not 
move  and  a  sudden  serial  action  of  these  triples  will  not 
take  place;  only  a  heavy  service  application.  If  the 
general  rule  to  allow  the  air  to  pass  out  of  the  brake  pipe 
at  the  brake  valve  or  conductor's  valve  in  cases  of  emer- 
gency or  danger  is  promptly  obeyed,  all  brakes  that  oper- 
ate will  be  applied  with  the  greatest  power  and  in  the 
shortest  time  possible  under  the  conditions. 

The  passenger  car  triple  shown  in  Plate  R  24  has  the 
graduating  valve  48  on  top  of  the  exhaust  valve  38  instead 
of  at  the  end  as  shown  in  the  next  cut  of  R-6.  Valve  48 
is  fitted  into  a  notch  in  the  piston  rod  so  that  it  moves 
with  the  piston  128,  having  its  seat  on  top  of  valve  38. 
When  the  triple  piston  makes  its  first  movement  in  a 
graduated  application,  valve  48  uncovers  the  air  port 
through  valve  38  and  allows  auxiliary  air  to  pass  into 
this  port,  although  air  cannot  pass  into  the  brake  cylinder 
till  the  exhaust  valve  has  moved  far  enough  to  open  the 
ports  into  the  cylinder.  Then  when  the  triple  piston 
moves  back  to  lap  position,  valve  48  moves  across  the  top 
of  38  and  covers  the  air  port ;  the  lost  motion  between 
the  ends  of  valve  38  and  the  shoulders  on  the  piston  rod 
allows  the  piston  and  valve  48  to  move  without  moving 
38.  In  this  triple  R-24,  the  passages  from  the  auxiliary 
to  the  brake  cylinder  through  the  quick-action  ports  of  the 
triple  are  much  larger  than  in  the  older  form,  so  that 
auxiliary  and  brake  cylinder  pressures  equalize  much 
quicker. 

The  improved  freight  triple  valve,  R-6,  is  shown  in 
emergency  positions,  vent-valve  piston  is  moved  down  so 
that  the  opening  of  port  F  through  the  stem  is  inside  the 


TRIPLE     VALVE     DEFECTS  239 

bushing  of  the  center  piece  130.  This  covering  of  port  F 
chokes  and  retards  the  flow  of  air  out  of  chamber  G  so 
that  the  vent-valve  piston  can  not  return  to  its  normal 
position  so  quickly.  It  thus  holds  vent-valve  71  away 
from  its  seat  longer,  which  makes  a  heavier  reduction  in 
brake  pipe  pressure.  In  all  the  later  triples  check  valve 
117  and  quick-action  valve  138  have  rubber  seats,  and  port 
F  is  in  the  stem  of  piston  129. 

This  later  style  of  port  F  operates  the  same  as  the  port 
through  the  piston,  in  each  style  the  air  from  G  can  pass 
to  the  brake  pipe  the  full  size  of  port  F. 


DEFECTS   OF   QUICK   ACTION   TRIPLE 

If  vent  valve  71  leaks,  or  is  held  off  its  seat,  there  will 
be  a  blow  at  the  round  port  M,  and  sometimes  at  the  two 
square  ports  J ;  also,  the  brake  may  not  release  as  brake 
pipe  pressure  can  not  be  raised  enough  to  move  triple  to 
release  position.  If  the  vent  valve  piston  stem  129  is  bent 
or  the  piston  sticks  in  the  cylinder  of  128,  valve  71  will 
be  held  open.  This  piston  stem  129  and  the  cylinder  of 
128  are  easily  damaged  by  improper  handling,  and  should 
be  carefully  handled  when  taken  apart.  A  small  leak  at 
valve  71  will  show  at  the  round  hole  M.  If  there  is  a 
blow  at  the  square  ports  J  in  the  triple  shown  in  Plate 
Q-6,  and  not  at  M,  or  at  N  in  the  triples  shown  in  R-6, 
air  is  probably  coming  from  the  quick-action  valve  138 
and  thence  past  the  stem  of  137,  which  is  not  an  air  tight 
fit  in  the  cast  iron  body  of  the  triple.  If  the  air  passing 
by  valve  138  can  not  go  by  stem  137,  it  will,  when  the 
triple  is  in  release  position,  pass  check  117  and  out  the 
exhaust  port  or  pressure  retainer,  or  leakage  groove.  A 
leaky  packing  ring  in  piston  128  will  affect  the  prompt 
movement  of  this  piston  to  release  position,  as  the  air 
can  leak  by  this  defective  ring  and  equalize  the  auxiliary 
with  the  brake  pipe  without  moving  the  triple  piston.  A 
leak  by  this  ring  will  not  affect  the  quick-action  operation 
of  piston  129.  If  either  of  these  rings  are  fitted  too  tight, 


240  TRIPLE     VALVE     DEFECTS 

this  particular  triple  piston  may  not  move  when  the  others 
do  in  the  initial  reduction  of  a  service  application,  and 
when  it  does  move  it  may  cause  quick-action  at  this 
triple  only.  If  the  packing  ring  in  piston  129  leaks,  the 
air  in  G  can  pass  out  by  this  ring  and  this  triple  is  not 
likely  to  go  into  quick-action. 

A  leak  under  the  seat  of  valve  38  will  allow  auxiliary 
air  to  blow  out  the  exhaust  steadily.  If  under  valve  48  in 
the  triple  shown  in  Plate  Q-6,  it  will  blow  at  the  exhaust 
when  the  triple  is  in  release  position.  With  the  triple 
shown  in  R-24  it  will  leak  in  lap  position  only,  and 
then  into  the  brake  cylinder.  If  the  packing  ring  in  either 
piston  128  or  129  is  too  tightly  fitted  or  gritty,  the  triple 
may  work  slower  than  the  others,  and  get  quick-action 
with  a  moderate  service  reduction;  this  will  vent  a  little 
brake  pipe  air  to  the  atmosphere  at  that  triple,  but  will 
not  cause  any  other  New  York  triples  to  work  quick- 
action.  If  the  stem  129  is  bent  or  cylinder  of  128  is  bent 
or  damaged,  it  may  produce  the  same  effect.  This  defec- 
tive triple  can  usually  be  located  by  the  flash  of  air  from 
ports  M  and  J  towards  the  ground  which  will  blow  the 
sand  or  dust.  This  brake  may  release  at  once  if  the 
pressure  in  the  brake  pipe  is  not  reduced  at  that  time 
below  that  at  which  that  auxiliary  and  brake  cylinder 
equalizes. 

Sand  works  into  the  ports  M,  N  and  J  and  may  cause 
the  quick  action  piston  137  to  stick  after  a  quick-action 
application ;  this  will  hold  valve  138  open  so  auxiliary  air 
will  leak  away. 

Leaks  by  the  gasket  between  the  triple  and  the  aux- 
iliary on  a  freight  brake,  or  the  triple  and  the  cylinder 
head  on  a  passenger  brake  allowing  auxiliary  air  to  pass 
to  the  cylinder,  will  give  a  steady  blow  at  the  exhaust 
port  while  the  triple  is  in  release  position. 

If  the  port  F  has  been  enlarged  or  the  packing  ring  in 
piston  129  is  a  poor  fit,  so  it  leaks,  this  triple  may  not  go 
into  quick-action  when  the  sudden  brake  pipe  reduction 
is  made. 


COMPENSATING    VALVE 


241 


The  Compensating  Valve  is  used  in  high  speed  service 
and  is  designed  to  reduce  gradually  the  high  brake  cylin- 
der pressure  in  an  emergency  application  with  110  pounds 
in  the  brake  pipe  and  auxiliary  to  60  pounds,  when  the 
valve  will  close  and  allow  no  more  air  to  escape  through 
it  from  the  cylinder. 


THE   COMPENSATING   VALVE 


It  consists  of  a  piston,  100,  that  moves  in  a  cylinder  or 
bushing  with  several  small  ports  in  its  side,  in  normal 
position  the  piston  covers  them  so  no  air  can  pass  out  the 


242  OPERATION    OF    COMPENSATING   VALVE 

ports.  Below  this  piston  is  a  diaphram  and  plate  fastened 
to  the  piston  that  prevents  the  passage  of  air  either  way. 
The  piston  is  held  up  in  normal  position  by  a  stiff  spring 
11,  the  tension  of  the  spring  is  adjusted  by  the  nut  12,  a 
•cap  nut  13  makes  an  air  tight  joint  at  the  bottom  of  the 
spring  box,  screwed  into  the  side  of  the  spring  box  is  a 
check  valve  85,  containing  a  valve  86  with  a  small  port  a 
drilled  through  it. 

The  brake  cylinder  is  connected  above  the  piston  at  A; 
a  connection  is  made  to  the  check  valve  case  85  from  the 
passage  H  in  the  side  of  the  New  York  quick-action  triple 
valve.  At  any  application  of  the  brake  air  from  the  cylin- 
der comes  into  A  and  gives  its  pressure  to  the  piston,  if 
this  pressure  is  any  greater  than  the  resistance  of  spring 
11  piston  100  will  move  down  and  uncover  the  air  ports  in 
the  side  of  the  bushing;  this  allows  cylinder  air  to  escape 
and  reduce  its  pressure  till  spring  11  has  power  to  force 
piston  100  up  and  close  the  ports.  A  thin  leather  gasket 
on  top  of  piston  makes  a  tight  joint  against  a  shoulder  of 
the  bushing  so  no  air  can  leak  out  till  the  piston  moves 
down. 

When  an  emergency  action  of  the  brake  is  made,  brake 
pipe  air  from  the  quick-action  triple  comes  through  a  pipe 
into  the  check  case  85,  forces  valve  86  off  its  seat  and 
•equalizes  in  chamber  B  in  the  spring  box.  Spring  87  seats 
valve  86  so  the  air  in  B  is  confined  there,  but  can  grad- 
ually flow  out  through  the  small  port  a  in  the  check  valve. 
Its  pressure  comes  against  the  diaphram  under  the  piston 
and  is  added  to  the  strength  of  spring  11,  holding  piston 
100  up  against  a  stronger  pressure  of  the  cylinder  air  than 
the  spring  alone  could.  This  prevents  the  cylinder  air 
from  blowing  out  at  this  valve  till  the  air  in  B  has  had 
time  to  escape  and  it  then  blows  down  slowly.  In  this 
manner  it  compensates  for  the  change  in  braking  power 
as  the  speed  of  the  train  reduces.  This  matter  of  a  change 
in  braking  power  with  a  change  of  speed  has  been  dis- 
cussed in  the  chapter  on  the  High  Speed  Brake. 

The  port  where  the  cylinder  air  enters  the  valve  at  A 


TYPE    J    TRIPLE   VALVE 


243 


is  restricted  so  the  air  can  not  flash  into  A  at  a  high 
pressure,  which  aids  in  graduating  the  flow  of  air  from 
the  cylinder  during  an  emergency  application  when  the 
110  pound  auxiliary  pressure  is  used. 

These  openings  are  of  different  sizes  for  different  sized 
brake  cylinders  to  make  the  small  ones  blow  down  at  the 
same  rate  of  time  with  the  large  ones. 


Full  Release. 


244  OPERATION    OF    TYPE    J    TRIPLE 

The  type  J  triple  here  shown  in  two  sectional  views 
and  a  diagrammatic  view  is  for  high  duty  passenger 
service,  it  is  both  quick-action  and  quick-service  and  by 
the  use  of  a  supplementary  reservoir  of  about  twice  the 
volume  of  the  regular  auxiliary  reservoir;  the  quick  re- 
charge after  a  service  application,  a  graduated  release  of 
the  brake  cylinder  air  and  a  high 'pressure  at  the  emer- 
gency application  are  secured. 

Referring  to  the  diagrammatic  view  of  the  release  and 
charging  position,  air  from  the  brake  pipe  passes  in  the 
regular  way  around  piston  10,  through  feed  groove  D 
into  E  and  the  auxiliary,  brake  pipe  air  also  passes  by 
check  valve  1  (this  valve  is  139  in  the  sectional  cut), 
into  chamber  F,  then  through  port  G  into  E,  so  the  aux- 
iliaries are  charged  from  two  sources.  Port  G  is  of  the 
proper  size  for  the  reservoirs  it  is  to  charge,  port  D  is 
small,  it  is  for  equalizing  the  pressures  during  slight 
fluctuations  in  brake  pipe  pressure.  Port  H  through 
graduating  valve  2  registers  with  port  I  through  slide 
valve  3  and  port  J  in  the  seat  so  the  supplementary  is 
charging  at  the  same  time  with  the  service  auxiliary.  Air 
from  the  brake  cylinder  can  pass  out  through  ports  Q, 
T,  cavity  W,  ports  X  and  Y.  The  safety  valve  is  con- 
nected to  the  brake  cylinder  at  port  Q  and  is  set  at  60 
pounds;  the  blow-down  attachment  that  operates  in- an 
emergency  application  only  is  shown  in  the  lower  part  of 
the  safety  valve. 

In  a  quick-service  application,  piston  10  closes  feed 
groove  D,  graduating  valve  2  is  moved  back  so  cavity  W 
no  longer  connects  ports  T  and  X,  this  closes  the  exhaust, 
port  I  is  covered  so  no  more  air  can  pass  to  and  from 
the  supplementary,  port  R  registers  with  S  in  valve  3, 
valve  3  next  moves  so  ports  G  and  K  register  as  well  as 
partly  opening  S  to  Q.  Auxiliary  air  flows  through  R, 
S  and  Q  to  the  cylinder ;  brake  pipe  air  flows  from 
chamber  F  in  a  small  volume  through  G,  K,  L,  M  and  N 
in  between  pistons  5  and  8;  these  pistons  are  not  air 
tight  so  the  air  passes  into  Q  without  moving  them,  this 


OPERATION    OF    TYPE    J    TRIPLE    VALVE  245 

flow  of  air  from  the  brake  pipe  makes  a  light  local  reduc- 
tion that  affects  the  next  triple  so  it  moves  to  service 
position  quicker  than  with  the  brake  valve  reduction 
alone.  When  the  reduction  at  the  brake  valve  stops  and 
piston  10  moves  back  to  lap  it  moves  valve  2  only  and 
laps  port  S  from  the  auxiliary  and  port  K  so  no  more  air 
passes  to  the  brake  cylinder.  In  a  full  service  with  a 
short  train  valve  3  is  moved  far  enough  to  lap  ports  G 
and  K  so  no  air  comes  from  the  brake  pipe;  ports  S  and 
Q  are  opened  wide,  thus  a  larger  amount  of  air  can  pass 
from  the  auxiliary  to  the  cylinder  at  each  triple  with  a 
short  train  than  with  a  long  one. 

In  a  restricted  release,  the  brake  pipe  is  recharged  a 
few  pounds  above  the  auxiliary  and  the  brake  valve  then 
lapped.  Piston  10  will  move  both  slide  and  graduating 
valves  to  release  position,  opening  exhaust  ports  from  Q 
around  to  Y;  the  recharging  port  G  allows  air  to  flow 
from  the  brake  pipe;  and  ports  J,  H  and  I  allow  air  to 
flow  from  the  supplementary.  This  air  from  the  sup- 
plementary will  raise  the  pressure  in  E  above  that  in  C 
so  piston  10  will  move  back  closing  port  D,  the  graduating 
valve  2  will  lap  ports  H  and  I  so  air  can  no  longer  flow 
from  the  supplementary  and  pressure  in  E  will  not  rise 
higher,  exhaust  ports  T  and  X  are  lapped  by  cavity 
W  moving  away  from  T.  As  main  slide  valve  3  will  not 
be  moved  in  this  operation  ports  T  and  X  will  still  register 
with  Q  and  Y  and  air  from  the  cylinder  can  pass  out 
very  slowly  through  the  small  port  Z,  connecting  T  and  X, 
this  allows  air  to  exhaust  from  the  cylinder  slowly  as 
long  as  valve  3  remains  in  this  position.  In  the  emer- 
gency application,  piston  10  and  valves  2  and  3  make  a 
full  travel  at  once,  port  Y  is  open  to  Q  so  that  auxiliary 
air  flashes  into  the  cylinder  through  a  large  port,  port  N 
is  uncovered  by  this  movement  of  valve  3  so  auxiliary  air 
passes  between  pistons  5  and  8.  Piston  5  moves  to  the 
left  and  opens  emergency  valve  7,  brake  pipe  flashes  into 
Q  and  the  cylinder;  piston  8  opens  valve  9  so  air  from 
the  supplementary  in  U  can  equalize  through  passage  Q 


246 


THE    K-4    TRIPLE    VALVE 


with    the    cylinder    and    service    auxiliary    giving    a    much 
higher  braking  power  than  in  the  service  application. 

The  Blow-down  valve  shown  in  the  bottom  of  the 
safety  valve  case  has  moderate  sized  ports  Bl  around  it 
so  in  a  service  application  the  air  from  the  cylinder  can 
pass  around  12  without  moving  it.  In  an  emergency 
application  the  air  comes  from  Q  so  fast  that  it  raises 
valve  12,  makes  a  tight  joint  at  its  top  edge,  this  prevents 
cylinder  air  getting  to  the  safety  valve  during  an  emer- 
gency application.  In  operating  the  J  triple  to  make  a 
gradual  release  charge  the  brake  pipe  sufficient  to  move 
piston  10  and  its  valves  to  release  position,  then  lap  the 
brake  valve,  the  brake  will  release  slowly  through  port  Z. 
To  have  it  release  faster,  recharge  the  brake  pipe  again 
to  move  piston  10  and  valve  2  then  lap  brake  valve  again, 
this  will  open  exhaust  port  wide  for  a  short  time,  you 
can  thus  release  the  brake  by  successive  steps  down  to 
zero.  See  explanation  of  question  55. 


The  K-4  Triple  Valve  of  the  New  York  Brake  Co., 
in  addition  to  the  quick-action  and  quick-service  features 
already  explained  in  J  Triple,  has  a  piston  stop  345  and 
its  spring  369 ;  an  exhaust  piston  339  that  during  a  re- 
tarded release  is  moved  to  the  left  and  chokes  the  exhaust 
port  with  its  stem  and  thus  restricts  the  exhaust.  At  a 


OPERATION   OF   K-4  TRIPLE  VALVE  247 

release,  if  brake  pipe  pressure  is  raised  much  higher  than 
the  auxiliary,  it  forces  triple  piston  334  its  full  travel 
against  the  tension  of  piston  stop  spring  369,  a  port  in 
slide  valve  then  allows  auxiliary  air  in  at  the  right  of 
exhaust  piston  339  and  force  it  to  the  left,  its  stem  then 
chokes  the  exhaust  opening  so  air  passes  out  slowly.  In 
this  position  piston  334  makes  a  tight  joint  against  the 
bushing,  no  air  will  pass  it  and  the  auxiliary  charges 
through  the  port  from  the  brake  pipe.  When  the  aux- 
iliary and  brake  pipe  pressures  are  nearly  equalized, 
spring  369  will  move  stop  345,  triple  piston  334  and  its 
valves  335  and  336  back  to  free  release  position,  this 
allows  air  to  pass  around  piston  334  through  feed  groove, 
also  opens  the  space  at  the  right  of  exhaust  piston  339  to 
the  exhaust,  so  this  piston  is  moved  back  by  its  spring 
347,  the  exhaust  port  is  then  full  sized.  A  leather  gasket, 
358,  on  the  exhaust  piston  prevents  a  leak  of  auxiliary  air 
past  the  piston  while  it  is  held  in  retarded  release  posi- 
tion. See  explanation  of  question  54. 


NEW  YORK  AIR    SIGNAL    VALVE 

The  Air  Signal  Valve  shown  in  section  on  this  page 
has  two  chambers,  A  and  B,  in  the  upper  and  lower  parts 
of  the  valve,  separated  by  a  rubber  diaphram  12.  Air 
from  the  main  reservoir  reduced  in  pressure  at  the  reduc- 
ing valve  to  40  pounds  enters  the  signal  valve  from  the 
signal  pipe  and  passes  into  chamber  A  through  the  small 
opening  d  which  serves  to  restrict  the  flow  of  air  into 
and  out  of  chamber  A.  From  A  air  passes  up  around  the 
posts  9  which  are  firmly  attached  to  the  diaphram  stem 
7.  Air  also  passes  through  the  opening  a  in  stem  7, 
and  through  the  very  small  hole  at  b  into  chamber  B. 
The  lower  end  of  stem  7,  when  in  its  normal  position, 
makes  a  tight  joint  on  the  top  of  post  4  around  the  plug 
5,  so  that  all  air  has  to  pass  through  b  when  charging  up 
chamber  B.  After  the  signal  equipment  is  charged  to 


248 


NEW    YORK    AIR    SIGNAL 


the  standard  pressure,  a  sudden  reduction  of  pressure  in 
the  signal  pipe  by  allowing  air  to  escape  at  the  car  dis- 
charge valve  will  also  reduce  the  pressure  in  chamber  A. 
The  air  in  B  cannot  equalize  through  b  fast  enough ;  so 


SIGNAL  VALVE         1903  MODEL. 

pressure  in  B  will  raise  diaphram  12,  also  raising  disc 
valve  10  off  its  seat  at  c;  air  then  passes  from  A  to  the 
whistle  through  e  and  gives  a  blast.  When  diaphram  12 
raises,  the  lower  end  of  stem  7  at  11  raises  off  the  post  4, 
air  from  chamber  B  can  then  pass  up  through  11  past 
plug  5,  which  is  taper  at  its  upper  end,  through  passage 
a  in  stem  7  and  equalize  quickly  with  the  air  in  chamber 
A.  The  diaphram  at  once  drops  to  its  normal  position 
with  stem  7  resting  on  post  4,  seating  valve  10  so  no  more 
air  passes  into  the  whistle.  Air  then  feeds  into  A  and  B 
till  the  pressures  are  equalized  with  the  signal  pipe,  when 
another  reduction  can  be  made  at  the  car  discharge  valve 
and  again  operate  the  signal  valve. 

The  older  type  of  New  York  Signal  Valve  is  con- 
structed like  the  1903  model,  except  that  the  opening  a 
passing  through  diaphram  stem  7  is  very  small,  and  air 


NEW    YORK    AIR    SIGNAL 


249 


passes  through  a  slowly  when  charging  up  B  and  out  of 
chamber  B  much  slower  when  the  pressure  in  A  is  re- 
duced and  diaphram  12  rises ;  this  causes  diaphram  to  re- 
main up  and  hold  valve  10  open  longer  than  necessary. 

REDUCING  VALVE. 


^•TO  MAIN  RESERVOIR 


The  disc  valve  10  and  chamber  A  are  the  same  in  both 
types  of  signal  valves;  the  bottom  part,  chamber  B  is 
much  larger  in  the  1903  model  than  the  older  type,  so 
there  is  a  larger  volume  of  air  in  chamber  B  of  the  1903 
valve. 

The  1903  model  charges  up  chamber  B  slowly;  when 
diaphram  12  raises,  air  equalizes  from  B  into  A  very 
quickly,  thus  giving  a  quick  closing  of  disc  valve  10. 

The  reducing  valve  used  with  the  New  York  signal 
apparatus  is  shown  in  section.  Diaphram  plate  6  is  held 
down  by  a  regulating  spring  9  when  there  is  less  than 
standard  pressure  in  A.  This  in  turn  holds  supply  valve 
5  off  its  seat  so  that  main  reservoir  air  entering  at  4  can 
pass  into  A  and  through  b  into  the  signal  pipe,  charging 
it.  A  rubber  diaphram  7  makes  an  air  tight  partition 
between  the  air  in  A  and  the  outside  air.  The  small 


250  REDUCING     VALVE     OPERATION 

holes  v  in  the  spring  cap  3  are  to  allow  any  air  that  may 
leak  past  7  to  escape  to  the  atmosphere.  When  the  press- 
ure in  A  reaches  the  standard  amount,  usually  40  pounds, 
diaphram  7,  stem  6  and  nut  8  are  raised  by  the  air  press- 
ure against  the  stiffness  of  spring  9.  This  allows  spring 
10  to  close  supply  valve  5  so  that  pressure  in  A  will  not 
raise  any  higher.  When  the  opening  of  a  car  discharge 
valve  or  a  leak  in  the  signal  pipe  or  its  connections  reduces 
the  air  pressure,  spring  9  forces  the  diaphram  down,  opens 
the  supply  valve;  this  allows  main  reservoir  air  to  feed 
into  the  signal  pipe  again. 

The  object  of  a  reducing  valve  is  to  maintain  signal 
pipe  pressure  lower  than  that  used  in  the  operations  of  the 
brake,  so  that  operating  either  the  brake  or  signal  will  not 
interfere  with  the  work  of  the  other.  The  opening  past 
the  supply  valve  is  made  small  so  air  will  pass  into  the 
signal  pipe  slowly  in  order  that  a  sufficient  reduction  can 
be  made  at  the  car  discharge  valve  of  any  car  to  operate 
the  signal  valve.  This  could  not  be  done  if  the  reducing 
valve  supplied  air  as  fast  as  the  car  discharge  valve  took 
it  out. 


OPERATING   THE    EQUIPMENT 

When  making  the  initial  or  first  service  reduction  in 
brake  pipe  pressure,  to  apply  the  brakes  lightly  on  a  train 
having  both  kinds  of  triple  valves  in  operation,  no  change 
in  the  manner  or  amount  of  reduction  is  needed,  as  both 
Westinghouse  and  New  York  triples,  if  in  good  order, 
will  apply  their  brakes  alike.  The  initial  reduction  should 
be  from  5  to  7  pounds,  depending  on  the  number  of  air 
brake  cars  operated;  the  length  of  the  entire  train  and 
the  speed  at  which  it  is  running.  A  short  train  will  not 
need  so  heavy  an  initial  reduction  as  a  longer  train. 
There  will  not  be  so  many  triple  valve  feed  ports  to  pass 
air  from  the  auxiliaries  to  the  brake  pipe,  which  tends 
to  prevent  movement  of  the  triple  piston,  and  the  volume 


OPERATING     THE     EQUIPMENT  251 

of  brake  pipe  air  is  less  in  a  short  train  than  in  a  long 
one;  so  the  reduction  through  the  brake  valve  is  made 
quicker,  which  moves  the  triples  quicker.  This  in  turn 
passes-  air  into  the  brake  cylinders  faster,  so  the  pistons 
move  over  the  leakage  grooves  with  less  loss  of  air 
through  the  grooves. 

On  a  long  train  the  first  reduction  may  be  7  to  9 
pounds  without  giving  serious  shocks,  unless  the  speed 
is  very  slow,  in  which  case  it  is  best  to  make  a  lighter 
reduction.  A  5  pound  initial  reduction  will  give  a  cylinder 
pressure  of  less  than  5  pounds  on  an  8-inch  travel  piston 
with  the  ordinary  triple  valves,  which  will  not  give  any 
shock  to  a  train.  With  K  triples  in  the  train  a  5  pound 
reduction  will  give  a  higher  cylinder  pressure  in  their 
cylinders.  If  the  train  is  moving  fast,  the  initial  reduction 
can  be  much  heavier;  especially  in  the  case  of  a  passenger 
train.  It  is  advisable  to  apply  the  brakes  with  considerable 
force  when  at  high  speed,  the  retarding  force  of  the  shoes 
on  the  wheels  is  less  in  proportion  than  at  slow  speeds. 

With  freight  trains,  at  whatever  speed,  allow  the  slack 
to  even  up  after  shutting  off  steam  before  applying  the 
brake,  then  apply  it  lightly  in  the  case  of  slow  speeds  to 
bunch  the  train  evenly  and  follow  up  with  other  reductions 
as  may  be  necessary  to  control  the  train.  Always  wait  at 
one  reduction  till  the  air  has  stopped  flowing  from  the 
brake  pipe  exhaust  of  the  brake  valve  and  the  triples  have 
had  a  chance  to  act  and  the  slack  to  even  up  before  making 
another  reduction. 

When  operating  the  1902  model  New  Youk  brake  valve, 
move  the  handle  to  first  service  position  notch  with  a 
short  train,  and  the  air  will  at  once  begin  to  discharge 
from  the  brake  pipe  through  an  opening  in  the  main 
slide  valve,  as  the  pressure  reduces,  the  cut-off  valve  will 
.close  the  opening,  it  will  entirely  close  when  the  pressure  is 
reduced  the  proper  amount  for  that  notch;  it  is  not  neces- 
sary to  return  the  handle  to  lap  position.  Succeeding  reduc- 
tions may  then  be  made  by  moving  the  handle  to  the  next 
service  notches  and  allowing  the  valve  to  graduate  the  flow 


252  OPERATING    THE    EQUIPMENT 

of  brake  pipe  air  and  stop  its  discharge,  or  the  handle  can 
be  stopped  between  the  notches.  When  the  last  graduating 
notch  is  reached  it  is  expected  that  a  reduction  of  20  to  23 
pounds  will  have  been  made  in  the  brake  pipe  pressure. 
With  a  long  train  it  may  be  necessary  to  go  to  the  second 
or  third  notch  in  order  to  get  a  proper  initial  reduction  on 
a  long  train.  If  quick  action  is  desired  at  the  triples, 
move  the  handle  to  the  emergency  position  for  the  first 
reduction  and  leave  it  there  till  the  train  has  stopped  or 
the  necessity  for  the  quick  stop  has  passed.  This  is  a 
general  rule  for  all  brake  valves  and  all  triples  in  cases 
of  emergency  or  danger  which  must  be  observed. 

With  the  older  type  of  New  York  brake  valve,  the 
Vaughn-McKee  valve,  in  order  to  have  the  valve  cut  off 
the  discharge  of  brake  pipe  air  automatically  in  a  grad- 
uated application,  the  valve  must  have  been  placed  in  full 
release  position  long  enough  to  discharge  all  air  from  the 
supplementary  reservoir  to  allow  brake  pipe  pressure  to 
move  the  equalizing  piston  and  the  cut-off  valve  to  their 
normal  positions.  It  must  then  be  moved  to  running 
position  to  recharge  the  supplementary  reservoir  from 
the  brake  pipe  air  till  it  equalizes,  after  which  the  piston 
would  operate  the  cut-off  valve  in  a  graduated  applica- 
tion. If  the  valve  was  only  placed  on  running  position 
to  release  brakes  and  moved  to  service  application,  the 
cut-off  valve  might  be  over  the  graduated  reduction  port 
so  no  air  could  pass  out  of  brake  pipe  and  it  would  be 
necessary  to  go  farther  back  towards  the  emergency 
notch  to  discharge  any  brake  pipe  air.  When  operating 
the  brake  with  this  valve  be  sure  to  go  to  full  release, 
when  releasing  brakes,  then  stop  on  running  position  an 
instant  if  you  expect  the  piston  to  operate  the  cut-off  valve 
in  a  graduated  service  reduction.  The  1902  model  brake 
valve  will  graduate  the  flow  of  brake  pipe  air  in  a  service 
application,  as  it  automatically  discharges  and  recharges 
the  supplementary  reservoir  when  at  lap  position  or 
towards  release.  As  the  only  proper  position  for  the 
brake  valve  at  the  moment  of  releasing  all  brakes  on  any 


OPERATING    THE    EQUIPMENT  253 

kind  of  a  train  or  engine  is  full  release,  this  precaution 
can  be  observed. 

With  a  short  train  or  lone  engine  the  brake  valve  of 
whatever  type  can  be  moved  from  full  release  to  running 
position  in  a  few  seconds  and  thus  avoid  overcharging  the 
brake  pipe  in  case  there  is  a  high  main  reservoir  pressure. 

With  a  long  brake  pipe,  leave  the  valve  in  full  release 
about  a  half  second  for  each  car  or  until  the  black  and  red 
hands  of  the  gauge  have  equalized  at  less  than  the  standard 
brake  pipe  pressure,  usually  70  pounds,  then  move  to  run- 
ning position  and  leave  it  there  till  the  next  application, 
unless  the  train  is  a  very  long  one,  when  it  is  not  unusual 
for  a  few  of  the  brakes  on  the  head  end  of  the  train  to 
apply  from  overcharged  auxiliaries,  the  head  ones  charging 
higher  than  those  on  the  rear  when  main  reservoir  air  is 
flowing  rapidly  into  the  brake  pipe.  If  any  set,  they  can  be 
kicked  off  by  going  to  full  release  for  an  instant.  The 
New  York  brake  valve  has  an  excess  valve  to  maintain  a 
difference  of  pressure  between  the  main  reservoir  and 
brake  pipe  so  the  instructions  about  carrying  excess  press- 
ure with  the  Westinghouse  D-8  brake  valve,  found  in  the 
previous  pages  of  this  book,  will  apply  to  the  New  York 
brake  valve.  Questions  19  and  65  refer  to  this  matter. 
Always  use  full  release  position  to  release  brakes  with 
any  valve,  and  it  is  a  vital  point  in  quick  recharging  of 
auxiliaries,  as  when  on  a  hill,  to  keep  the  valve  in  full 
release  as  long  as  possible. 

Many  railroads  have  imperative,  iron-clad  rules  about 
certain  air  brake  work  which  are  made  to  prevent  careless 
or  unskillful  air  brakemen  from  cloing  considerable  dam- 
age. While  only  a  very  few  of  the  men  handling  the  brake 
may  be  in  the  class  mentioned,  yet  the  rule  must  be 
observed  by  the  skillful  as  well  as  the  careless  ones. 
One  of  these  rules  is :  "Do  not  release  the  brakes  on  a 
long  train  when  running  at  a  slow  speed,  but  come  to  a 
full  stop  first."  This  speed  is  usually  below  eight  miles 
an  hour.  This  rule  is  made  because  the  shocks  to  the 
train  caused  by  the  slack  running  in  or  out  of  the  train 


254  OPERATING    THE    EQUIPMENT 

quicker  than  all  the  brakes  can  release,  is  usually  certain 
to  break  the  train  in  two  or  more  parts.  With  the  use 
of  an  additional  engine  and  tender  brake,  either  the 
Straight  Air  or  the  ET  brake;  retaining  valves  on  engine 
and  tender  brakes  or  cocks  so  arranged  as  to  hold  the 
engine  and  tender  brakes  applied,  or  sufficient  K  triples 
at  the  head  end,  the  train  brake  can  be  released  at  a  slow 
speed  without  serious  shocks.  Retainers  depend  on  tight 
piston  packing  and  tight  joints  for  their  value.  If  the 
joints  or  packing  leathers  leak,  retainers  are  useless  for 
this  purpose.  This  "iron-clad  rule"  applies  as  well  to  long 
passenger  trains,  when  consisting  of  over  twelve  coaches, 
a  release  at  slow  speed  without  the  use  of  some  device 
on  the  engine  to  hold  the  slack  is  almost  certain  to  break 
the  train  in  two  parts.  The  size  of  the  main  reservoir 
and  amount  of  excess  pressure  have  considerable  to  do 
with  the  ease  and  certainty  of  releasing  all  brakes  quickly 
on  a  long  train;  large  volume  and  high  excess  make  the 
operation  sure  on  a  long  train.  You  should  remember 
that  there  is  more  difference  in  the  reservoir  and  brake 
pipe  pressures  after  a  20-pound  reduction  than  after  a 
5-pound  reduction.  This  may  explain  the  reason  for 
stuck  brakes  on  a  long  train  after  a  light  application. 
This  matter  is  treated  of  in  questions  12,  61  and  108. 
One  prominent  railroad  handling  long  trains  of  air  braked 
ore  cars  allows  the  release  of  a  few  brakes  at  a  time  when 
running  at  a  slow  speed,  instead  of  coming  to  a  full  stop. 
After  a  full  application  or  nearly  so,  when  necessary  to 
release  a  few  of  the  brakes  at  a  time  and  allow  the  train 
to  keep  moving  during  releasing,  the  brake  valve  is  moved 
from  lap  to  running  position  for  an  instant  to  raise  the 
brake  pipe  pressure  a  very  little,  not  over  a  pound,  when 
a  few  brakes,  usually  those  near  the  head  end  of  the  train 
will  release.  The  next  time  the  valve  is  placed  in  running 
position  for  an  instant,  brakes  will  release  in  various 
parts  of  the  train;  this  operation  can  be  repeated  till  the 
brake  pipe  pressure  is  raised  about  5  pounds  in  all. 
Between  each  release  allow  the  slack  to  even  up.  If  this 


TRACING     THE     AIR  255 

work  is  skillfully  done  and  the  triples  are  in  good  order, 
very  few  brakes  will  remain  applied  after  the  5-pound 
raise  in  pressure.  Then  with  good  stiff  excess  go  to  full 
release  and  quickly  charge  the  brake  pipe  up  its  entire 
length  to  ensure  that  all  triples  are  moved  to  release 
position.  This  process  has  a  much  different  effect  on  a 
train  at  slow  speed  from  releasing  all  triples  with  the  same 
recharge  of  brake  pipe.  It  also  operates  better  on  a  train 
of  ore  cars  which  are  either  all  loaded  or  all  empty,  than 
on  an  ordinary  freight  train  having  loads  and  empties 
mixed  up  in  the  train;  for  this  reason  it  takes  great  skill 
to  handle  a  freight  train  in  this  manner.  A  full  release  of 
all  triples  from  one  movement  of  the  brake  valve  at  slow 
speed,  usually  breaks  the  train  in  two;  for  that  reason  all 
roads  condemn  the  practice.  In  releasing  brakes  an 
engineer  should  know  the  grades  and  how  they  affect  the 
bunching  or  stretching  of  a  train. 

One  of  the  questions  usually  asked  in  an  air  brake 
examination  is  "trace  the  air  through  the  air  brake  system; 
tell  where  it  goes  and  how  it  operates  the  various  parts 
of  the  equipment."  Some  air  brake  instructors  ask  this 
question  at  the  beginning  of  their  examination.  As  a 
complete  answer  to  this  question  requires  a  good  knowl- 
edge of  the  entire  equipment,  in  this  book  it  is  left  till 
the  last. 

With  the  Westinghouse  equipment,  air  from  the  atmos- 
phere enters  at  the  inlet  or  receiving  valves  of  the  air 
pump,  when  the  piston  moves  in  the  air  cylinder,  filling 
the  space  left  by  the  piston.  As  the  piston  makes  a  stroke 
the  air  in  the  cylinder  that  is  compressed  passes  by  the 
discharge  valves  into  the  main  reservoir  and  from  there 
to  the  brake  valve,  where  it  is  above  the  rotary  valve. 
In  full  release  position  it  passes  through  the  direct  supply 
port  in  rotary  into  the  pocket  in  the  rotary  seat,  around 
the  partition,  up  into,  the  large  cavity  in  the  lower  side  of 
the  rotary,  then  into  the  brake  pipe.  At  the  same  time 
it  passes  through  the  feed  port  in  the  rotary  and  the  pre- 
liminary exhaust  port  into  chamber  D  also  through  the 


256  TRACING     THE     AIR 

equalizing  port  into  chamber  D ;  main  reservoir  air  goes 
to  red  hand  of  the  duplex  gage  and  pump  governor  and 
warning  port  to  atmosphere.  From  chamber  D,  air  goes 
to  the  black  hand  of  gage. 

In  running  position  air  passes  through  the  running 
position  or  feed  port  into  the  feed  valve  and,  until  the 
supply  valve  closes,  on  into  the  brake  pipe.  In  this  posi- 
tion air  passes  from  the  brake  pipe  up  into  the  cavity  in 
the  rotary  and  then  to  chamber  D  through  the  equalizing 
port.  With  the  D-8  or  1899  valve  in  running  position  air 
passes  through  feed  port  in  rotary  to  the  excess  valve ; 
by  the  excess  valve  into  brake  pipe.  With  D-8  valve  brake 
pipe  air  goes  to  the  governor,  with  the  other  valves,  main 
reservoir  air  operates  the  governor.  When  the  governor 
operates  air  flows  past  the  diaphram  valve  in  over  the  air 
piston  and  some  air  passes  out  the  vent  port. 

The  air  in  chamber  D  flows  into  the  brake  valve  reser- 
voir with  all  types  of  brake  valve.  Brake  pipe  air  flows 
back  until  it  reaches  an  angle  cock  or  stop  cock  that  is 
closed.  It  flows  into  every  triple  valve  that  is  cut  in  and 
connected  to  the  brake  pipe,  pressing  against  the  bottom  or 
brake  pipe  side  of  the  triple  piston.  When  this  piston  is 
in  release  position  air  flows  through  the  feed  groove 
around  the  triple  piston  into  the  auxiliary  reservoir  till 
the  pressures  are  equalized.  Air  also  passes  up  the  pipe 
to  the  conductor's  valve.  When  the  pressures  in  the  brake 
pipe  and  auxiliary  have  equalized  at  70  pounds  the  brake 
is  ready  for  an  application;  we  will  explain  a  service 
application  first. 

Moving  the  handle  of  the  rotary  to  service  position 
first  laps  the  port  that  admits  main  reservoir  air  to  the 
brake  pipe,  closes  the  equalizing  port  between  chamber  D 
and  the  brake  pipe  and  opens  the  preliminary  exhaust  port 
so  chamber  D  air  escapes  to  the  atmosphere.  This  reduces 
chamber  D  pressure  over  the  equalizing  piston  brake  pipe 
pressure  then  raises  this  piston,  which'  opens  the  brake  pipe 
exhaust  valve  so  brake  pipe  air  flows  to  the  atmosphere, 
reducing  the  pressure  at  each  triple  valve.  The  triple 


TRACING     THE     AIR  257 

piston  moves  towards  the  reducing  pressure,  closing  the 
feed  port,  moving  the  graduating  valve  to  open  its  port  in 
the  slide  valve,  the  slide  valve  moves  so  the  exhaust  port 
is  closed,  next  opening  the  air  port  to  the  brake  cylinder 
so  that  auxiliary  air.  flows  into  the  brake  cylinder  and 
pushes  out  the  brake  piston  which  sets  the  brake.  See 
question  37  for  the  Operation  of  the  Distributing  Valve. 

To  release  the  brake,  the  brake  valve  is  placed  in  full 
release  position;  main  reservoir  air  passes  into  the  brake 
pipe  as  already  described.  This  moves  the  triple  valves 
to  release  position,  closing  the  air  ports  to  the  brake 
cylinder,  opening  the  exhaust  port  so  the  air  can  flow 
from  the  cylinder  to  the  atmosphere  and  opening  the 
feed  groove  so  brake  pipe  air  can  flow  into  the  auxiliary. 
Air  also  flows  into  chamber  D  and  brake  valve  reservoir. 

To  release  the  ET  brake  the  brake  valve  must  be  in 
running  position,  or  the  independent  valve  in  release 
position. 

If  a  retaining  valve  is  used,  brake  cylinder  air,  after 
leaving  the  exhaust  port,  passes  through  a  pipe  to  the 
retainer,  when  this  valve  is  in  release  position  the  air 
passes  directly  out.  If  the  valve  is  in  retaining  position 
air  pressure  raises  the  valve  and  passes  up  into  the  case 
of  the  retainer  and  then  out  through  the  small  opening 
in  the  case  till  the  pressure  drops  to  15  pounds,  when 
the  valve  seats  and  holds  the  air  in  the  brake  cylinder  till 
the  retainer  is  turned  to  release  position. 

When  making  an  emergency  application  of  the  brake 
the  brake  valve  is  placed  in  emergency  -position.  Brake 
pipe  air  passes  out  very  rapidly  through  the  direct  exhaust 
port  at  the  same  time  chamber  D  air  passes  out  at  the 
preliminary  exhaust  port  of  the  automatic  brake  valve. 
Air  passes  out  of  the  brake  pipe  so  rapidly  that  the  triple 
valve  cannot  reduce  auxiliary  pressure  as  shown  in  service 
application,  auxiliary  air  pressure  moves  the  piston  full 
stroke  at  once,  auxiliary  air  passes  by  the  removed  corner 
of  the  slide  valve  through  emergency  port  and  on  top  of 
the  emergency  piston,  pushing  it  down,  this  opens  the 


258  TRACING     THE    AIR 

emergency  valve  and  allows  brake  pipe  air  to  pass  into 
the  brake  cylinder,  which  sudden  reduction  of  brake  pipe 
pressure  operates  the  next  triple  quick-action  and  so  on 
throughout  the  whole  train.  At  the  same  time  auxiliary 
air  passes  through  the  tail  port  in  the  slide  valve;  also 
some  air  passes  by  the  emergency  piston  into  brake  cylin- 
der till  the  pressures  equalize.  When  the  brake  is  set 
by  opening  the  conductor's  valve  or  by  the  train  breaking 
in  two,  the  operation  is  the  same. 

In  releasing  brakes  after  an  emergency  application,  the 
flow  of  air  is  the  same  as  with  a  service  application.  We 
will  add  to  this  answer  the  signal  equipment:  The  main 
reservoir  air  flows  through  the  reducing  valve  till  it 
reaches  a  pressure  of  45  pounds;  if  the  reducing  valve  is 
adjusted  for  that  pressure.  Air  flows  into  the  air  signal 
pipe  back  to  each  car  discharge  valve.  On  the  engine  it 
passes  from  the  signal  pipe  into  the  upper  part  of  the 
signal  valve,  over  the  rubber  diaphram  into  A,  it  also 
passes  down  to  the  lower  part  of  the  valve,  up  by  the 
stem  10  slowly  into  chamber  B  until  the  pressure  equalizes 
there  with  the  signal  pipe.  When  the  whistle  is  to  be 
operated  from  the  train,  the  car  discharge  valve  on  the 
car  is  opened,  air  passes  out  of  the  signal  pipe  to  the 
atmosphere.  This  reduces  signal  pipe  pressure,  when  the 
reduction  affects  the  pressure  over  the  diaphram  in  the 
signal  valve,  the  pressure  under  the  diaphram  not  being 
reduced  so  quickly,  air  under  it  in  B  raises  the  diaphram 
and  with  it  the  valve  10,  so  that  air  flows  out  there  to  the 
whistle,  giving  a  blast  When  the  valve  10  is  raised,  air 
in  B  flows  past  the  flattened  sides  of  this  stem  to  the 
whistle;  this  quickly  reduces  the  pressure  in  B  and  the 
diaphram  drops,  pushing  valve  10  to  its  seat  so  no  more 
air  passes  to  the  whistle.  As  soon  as  the  brake  pipe 
pressure  falls  below  45  pounds  the  reducing  valve  opens 
and  begins  to  feed  main  reservoir  air  into  the  signal  pipe 
slowly,  as  the  opening  through  the  valve  is  restricted  or 
choked.  If  the  air  could  pass  into  the  signal  pipe  at  the 
reducing  valve  as  fast  as  it  can  pass  out  at  a  car  discharge 


TRACING     THE     AIR  259 

valve,  no  reduction  would  be  made  in  the  signal  pipe 
pressure. 

With  the  New  York  brake,  the  course  of  the  air  is  a 
little  different.  Air  flows  from  the  atmosphere  through 
the  receiving  valves  into  the  air  cylinders  as  the  air 
pistons  move  up  and  down.  The  air  in  the  high  pressure 
air  cylinder  goes  direct  to  the  main  reservoir  when  it  is 
compressed.  The  air  in  the  low  pressure  air  cylinder, 
when  compressed,  passes  into  the  high  pressure  air  cylin- 
der and  from  there  into  the  main  reservoir,  thence  to  the 
brake  valve  around  and  on  top  of  the  main  slide  valve; 
main  reservoir  air  goes  to  the  red  hand  of  the  gage  and 
brake  pipe  air  to  the  black  hand.  If  a  single  governor 
is  used  it  is  operated  by  brake  pipe  air,  if  a  duplex  gover- 
nor one  side  by  brake  pipe  air  and  the  other  by  main 
reservoir  air.  When  in  release  position  it  passes  directly 
into  the  brake  pipe  and  from  the  brake  pipe  into  chamber 
D  and  the  supplementary  reservoir  with  the  1902  model 
valve.  With  the  old  style  brake  valve,  on  release  position 
the  air  in  the  supplementary  reservoir  and  chamber  D 
passes  out  through  a  small  cavity  in  the  slide  valve  to  the 
atmosphere;  this  allows  brake  pipe  pressure  to  move  the 
equalizing  piston  to  its  normal  position.  On  running 
position  the  main  reservoir  air  passes  by  the  excess  valve 
and  then  into  the  brake  pipe;  brake  pipe  air  passes  into  the 
supplementary  reservoir  with  the  brake  valve  in  this 
position. 

The  brake  pipe  air  passes  back  through  the  brake  pipe 
to  each  triple  valve  that  is  cut  in.  At  the  triple  valve  the 
air  passes  through  the  port  F  in  the  vent  valve  piston  and 
if  the  main  piston  is  not  already  in  release  position, 
moves  it  there.  Air  then  passes  through  the  feed  groove 
into  the  auxiliary  until  the  pressure  there  has  equalized 
with  the  brake  pipe.  With  the  Automatic  Control  Valve 
the  course  of  air  is  explained  at  the  operation  of  that 
valve. 

With  a  service  application,  the  slide  valve  in  the  brake 


260  TRACING     THE     AIR 

valve  is  moved  till  the  service  port  is  open,  brake  pipe  air 
then  flows  direct  to  the  atmosphere  until  its  pressure  is 
reduced  so  the  pressure  of  the  air  in  the  supplementary 
reservoir  can  move  the  piston,  closing  the  cut-off  valve 
and  stopping  the  escape  of  brake  pipe  air. 

This  reduction  of  brake  pipe  pressure  extends  to  each 
triple,  auxiliary  air  pressure  moves  the  triple  piston, 
graduating  valve  and  slide  valve ;  first  closing  the  feed 
groove,  next  the  exhaust  port  and  then  opening  the  air 
port  so  air  passes  from  the  auxiliary  to  the  cylinder. 
The  air  in  the  space  G,  between  the  main  triple  piston 
and  the  vent  valve  piston  passes  out  through  port  F  so 
the  vent  valve  piston  does  not  move  in  a  service  application. 

In  an  emergency  application  the  slide  valve  in  the 
brake  valve  is  moved  to  emergency  position.  Brake  pipe 
air  passes  rapidly  out  through  the  large  ports  in  the  slide 
valve,  reducing  brake  pipe  pressure  so  rapidly  that  the 
triple  pistons  make  a  quick  stroke.  As  the  air  between 
the  two  pistons  cannot  pass  through  port  F  quickly  enough, 
the  vent  valve  piston  moves  with  the  main  piston,  unseats 
the  vent  valve;  this  allows  brake  pipe  air  to  flow  to  the 
atmosphere.  The  air  also  pushes  against  the  quick  action 
piston,  moving  it  over  and  with  it  opens  the  quick-action 
valve,  which  permits  auxiliary  air  to  flow  through  the 
passages  into  the  cylinder,  the  check  valve  preventing  this 
air  from  flowing  back  from  the  cylinder.  Auxiliary  air 
also  flows  into  brake  cylinder  through  the  service  port  at 
the  graduating  valve.  In  releasing  the  brake  the  flow  of 
air  has  already  been  described. 

The  course  of  air  through  the  signal  equipment  is  the 
same  as  described  with  Westinghouse  signal,  except  that 
air  passes  from  chamber  A  to  chamber  B  through  a  small 
port  b  when  charging  up  the  signal  valve,  and  out  of  B 
around  the  plug  4  to  chamber  A,  when  the  signal  valve 
operates. 


AIR  BRAKE  EXAMINATION  QUESTIONS 

1.  What    are    the    essential    parts    of    the    automatic 
•brake?     What  does  each  part  do? 

2.  Can  you  trace  the  course  of  the  steam  through  the 
steam  end  of  the  air  pump?     Can  you  trace  the  course  of 
the   air   through   the   pump? 

3.  How   should   the  pump   be   started   and   lubricated? 

4.  If  the  pump   stops  after  working  good   for  a  time, 
where  is  the  trouble  likely  to  be? 

5.  If   it   makes    a   quick   stroke   one   way   and    a   slow 
stroke  the  other,  where  is  the  trouble  likely  to  be? 

6.  What  are  the  principal  causes  for  a  pump  running 
hot? 

7.  If   the    main    reservoir   is   partly   filled   with    water, 
which    will    it    affect    the    most,    setting    or    releasing    the 
brake?     Why?     How   often   should   it   be   drained? 

8.  What  might  prevent  the  governor  shutting  off  the 
steam  and  stopping  the  pump  when  maximum  pressure  is 
obtained? 

9.  Where  would  you  look  for  the  trouble  if  governor 
stops  the  pump  at  much  less  than  standard  pressure? 

10.  How    do   you    adjust   the    governor   with    the    ET 
brake? 

11.  Should  you  test  the  engine  and  tender  equipment 
for  leaks? 

12.  How  do  you  test  for  leaks  in  main  reservoir  and 
pipes  from  pump  to  brake  valve? 

13.  What  other  parts  of  the  equipment  gets  air  from 
the  main  reservoir  besides  the  brake  pipe? 

14.  How   do  you  test   for  a  leak  in  brake  pipe?     In 
signal  line? 

15.  How  do  you  locate  a  leak  that  lets  off  the  brake? 

16.  What   pressure    should   you    have   before    testing? 

17.  What  controls   the  excess   pressure  with   the   H-5 
and  H-6  brake  valve?     With  the   F-6  valve?     With   the 
New  York  brake  valve? 


262  EXAMINATION    QUESTIONS 

18.  How  many  kinds  of  engineer's  brake  valves  have 
we  in  service  on  this  road? 

19.  Can   you   trace   the   air  through   each   of  them? 

20.  Explain  the  principle  of  operation  of  the  engineer's 
equalizing  discharge  brake  valve. 

21.  Describe    its    operation    to    apply    the    brake    with 
service   or   emergency    applications,   and    in   releasing   the 
brake. 

22.  Why  is  excess  pressure  necessary?     Do  you  need 
the  most  with  a  large  main  reservoir  or  a  small  one? 

23.  Is  more  excess  needed  to  release  all  the  brakes  on 
a  long  train  than  on  a  short  one  ? 

24.  How    do    you    regulate    the    excess    pressure    with 
the  H   type   brake  valve?     With  the   1892   model   or   F-6 
valve  ? 

25.  Name  the  different  positions  of  the  brake  valve. 
What  extra  position  has  the  type  H  brake  valve? 

26.  What  ports   are  open   and   what  ports   are  closed 
in  each  position? 

27.  Where    does    main    reservoir    pressure    begin    and 
end? 

28.  Where   does  brake  pipe  pressure  begin  and   end? 

29.  Where   does   auxiliary   pressure   begin? 

30.  What  is   the  equalizing  port  for?     Is   it   open    in 
all  positions  of  the  brake  valve? 

31.  Do   leaks  in  the  brake  valve  affect  the  operation 
of  the  brakes?     Explain  how. 

32.  Do     you     consider    a    cut     rotary    valve    or    seat 
dangerous? 

33.  Will    using    the    valve    in    emergency    instead    of 
service  application  cause  this  cutting  any  quicker?    Why? 

34.  What  is  the  purpose  of  the  small  reservoir  con- 
nected  to   the   equalizing   discharge   valve? 

35.  If  the  pipe  leading  from  valve  to  small  reservoir 
is  broken  off  or  leaking  badly,  what  will  you  do  ? 

36.  Where   is   the   first   air   taken   from    in   making   a 
service  stop?     What  port  does  it  blow  out  of? 

37.  Where   does    it   come    from?     Where   next? 


EXAMINATION    QUESTIONS  263 

38.  Does    air    ever    blow    out    of    brake    pipe    exhaust 
when  releasing  the  brake?     Why? 

39.  Do   you   hear   it   when   releasing   brake    on   engine 
and  tender   only?     Do  you   hear   it  with   a  train   of  over 
two  cars?     Do  you  hear  it  with  the  H  type? 

40.  If  you   are   connected   to  more  than   two   air  cars 
and  heard  that  blow,  what  would  it  indicate? 

41.  How  do  you  know  that  the  brake  valve  is  working 
properly  ? 

42.  When  applying  the  brakes  can  you  tell  about  how 
many  cars  are  connected  with   air  to  the  brake  valve  by 
the  amount  of  air  escaping  from  the  brake  pipe  exhaust? 
How  do  you  make  this  test? 

43.  How  much  do  you  reduce  the  brake  pipe  pressure 
from  70  pounds  to  set  the  brake  as  tight  as  possible? 

44.  Why  will  this   reduction  do   that? 

45.  What   is   the   difference   between   a    reduction   and 
an  application? 

46.  Does   the    length    of   travel    of   brake   piston   have 
anything  to  do  with  the  pressure  when  brake  is  full  set? 
How?     Explain   fully. 

47.  In   making   a   service   stop   why   should   the   brake 
valve  not  be  moved  past  the  service  application  position? 

48.  Is  this  movement  of  .the  brake  valve  liable  to  kick 
off  some  of  the  head  brakes?     Why? 

49.  What  is  the  proper  position  to  place  brake  valve 
in  after  releasing  brakes  if  they  are  to  be'  set  again  im- 
mediately?     Why?      Explain    fully. 

50.  What  are  the  functions  or  uses  of  the  triple  valve? 

51.  How  many  forms  in  use  on  this  road?     Describe 
each  form. 

52.  Where  does  all  the  air  come  from  that  enters  the 
brake  cylinder   through  the  plain   triple   when   setting  the 
brake  ? 

53.  Does  all  the  air  that  goes  into  the  brake  cylinder 
of  a  quick-acting  brake   come   from   the   auxiliary? 

54.  Please  explain  the  action  of  the  quick-action  triple 
when   used  in  the  emergency  application. 


264  EXAMINATION    QUESTIONS 

55.  Can  you  get  the  emergency  action  after  a  service 
application? 

56.  Does  it  take  a  sudden  reduction  of  pressure  right 
at  the  triple  to  work  the  quick-action  valves  or  will  a  slow, 
heavy   reduction   do   this?     Why? 

57.  If  three  or  four  cars  at  the  head  end  of  the  train 
do  not  have  quick-action  triples  working,  can  you  get  the 
emergency   application   behind    these   cars   by    a    reduction 
at  the  brake  valve?     How  many  cars  will  the  quick-action 
"jump  over?" 

58.  What  is  the  function  of  the  graduating  valve? 

59.  Where  is  it  located  and  how  does  it  operate? 

60.  If   the   graduating  valve   leaks   on   its   seat,   is   the 
brake  connected  to  that  triple  liable  to  release  on  a  partial 
application?     On   a   full   application?     Why   is   this? 

61.  What  is  the  function  of  the  graduating  stern  and 
spring? 

62.  If  this   spring  is  very  weak  or  missing,  how  will 
it  affect  the  work  of  the  triple  valve? 

63.  How^does   the   air   get   from   the   brake   pipe   into 
the  auxiliary  with  the  ordinary  triple?     With  the  K  type? 

64.  Why  is  this  port  so  small?     Could  the  brakes  be 
set  and  released  as  certainly  on  a  long  train  if  this  port 
was  much  larger?     Would  auxiliaries  charge  evenly? 

65.  In   what   position   of   the   triple   valve   is   the   port 
open? 

66.  How   rapidly   does   an   empty   auxiliary  charge   up 
to  70  pounds  with  70  in  the  brake  pipe? 

67.  How  rapidly  from  50  pounds  up  to  70  pounds? 

68.  What  regulates  the  time  of  charging  each  different 
sized  auxiliary? 

69.  If  one  auxiliary  is  charged  up  higher  than  another 
is  the  brake  likely  to  creep  on?     Is  it  liable  to  take  place 
when  coupling  up  an  air  brake  train?     Explain  why. 

70.  Why  is  it  dangerous  to  apply  and  release  the  brake 
repeatedly   in   making   one   station   stop? 

71.  Does  this   apply  to  a  release   and   second  applica- 


EXAMINATION     QUESTIONS  265 

tion  at  a  slow  speed  on  slippery  track?     With  a  passenger 
train?     With  a  freight  train? 

72.  Do    you    understand    that    brake    cylinders    have 
leakage  grooves?     Where  are  they  located  and  how  long 
are  they?     What  are  they  for? 

73.  Do   you   allow   for   them   when   setting  the   brake? 
How? 

74.  As    a    rule    how    much    reduction    in    brake    pipe 
pressure    is    necessary    to    ensure    that    brake    piston    goes 
past  the  leakage  groove? 

75.  Does  a  long  train  require  more  than  a  short  train? 
Why? 

76.  What  should  be  done  after  coupling  to  an  air  brake 
train  before  pulling  out? 

77.  What  pressure  should  you  have  in  brake  pipe  and 
auxiliaries  before  testing  the  brake? 

78.  How   do  you  know  when  you   have  70  pounds   in 
the  auxiliaries? 

79.  What  tests  of  air  equipment  are  called  for  by  our 
rules?     Explain   fully  how   these  tests   should  be   made. 

80.  Are  you   required  to  test  retaining  valves?     How 
is  this  done? 

81.  If   a   brake   is    broken    or   disabled,   how   will   you 
prevent  it  working  on  that  car  and  let  the  brakes  work  on 
other  cars? 

82.  How    do    you    cut    out    the    brake    on    engine    or 
tender  ? 

83.  Is  it  necessary  to  release  the  brake  before  cutting 
it  out? 

84.  How  does  the  length  of  the  piston  travel  affect  the 
work  of  the  brake?     If  it  is  too  long?     If  it  is  too  short? 

85.  What  is  the  proper  piston  travel  ?     For  passenger 
cars  ?     For  freight  cars  ?     For  engine  brakes  ? 

86.  How  is  the  slack  taken  up  to  secure  this  adjust- 
ment ? 

87.  Should  the  triple  be  cut  out  before  adjusting  the 
levers    to    avoid    injury    to    the    workman    in    case    brake 
goes  on? 


266  EXAMINATION    QUESTIONS 

88.  At  what  travel  should  the  driver  brake  piston  be 
adjusted?     How  is  the  slack  of  a  six-wheel  brake  taken 
up? 

89.  What  is  necessary  in  order  to  have  all  the  brakes 
work  alike? 

90.  When  brakes  go  on  suddenly  and  are  not  operated 
by  the  engineer,   what   should  you  do?     To  what  causes 
would  you  assign  this? 

91.  If  an  air  brake  train  breaks  in  two,  how  do  you 
proceed  to  get  train  ready  to  go  ahead  again?     How  do 
you  proceed  in   case  of  a   bursted   hose?     How  can  you 
help  trainmen  to  locate  it? 

92.  Would  it  be  necessary  in  these  cases   to  make  a 
terminal  test? 

93.  If,    after   releasing   train   brake   there    is    a    steady 
leak    from    the    exhaust    port   of   the    triple,    what    is    the 
trouble  ? 

94.  What  precautions  must  be  observed  in  making  a 
stop  with  a  "part  air"  freight  train?     What  with  a  lonpf, 
"full  air"  train? 

95.  In  making  a  stop  with  a  freight  train,  when  would 
you  let  off  the  brakes  to  make  a  smooth  stop?     Why? 

96.  When   with   a  passenger   train?     Wrhy? 

97.  What  is  the  pressure  retaining  valve,  what  is  its 
use  and  how  is  it  operated?    Are  there  several  kinds? 

98.  How  many  pounds  of  air  is  it  intended  to  close 
up  on  and  hold  in  the  brake  cylinder? 

99.  Does    the    brake    release    any    slower    till    it    gets 
down  to  this  pressure,  and  how  is  it  done? 

100.  Can  you  get  the  emergency  action  of  the  brake 
with  the  pressure   retainers   holding  15   pounds? 

101.  In  descending  a  grade,  how  can  you  best  keep  a 
train  under  control? 

102.  When  two  or  more  engines  are  coupled  together, 
which  engineer  should  do  the  braking?     Why? 

103.  How    will     you     proceed    to    give     the     leading 
engineer  complete  control  of  the  train?     What  should  the 
second  engineer  do? 


EXAMINATION    QUESTIONS  267 

104.  If    there    is    no    cut-out    cock    on    second    engine 
under  the  brake  valve,  what  should  be  done? 

105.  How  does  the  air  signal  equipment  operate? 

106.  What   pressure    should   be   carried    in   the    signal 
line?     How  do  you  know  you  have  this  pressure? 

107.  What  causes  the  whistle  to  blow  each  time  the 
brake  is  released?     What  makes  it  repeat  the  signal? 

108.  Will   a   leak    in   the   train    signal   pipe    affect   the 
working  of  the  whistle?     Explain. 

109.  Explain  the  meaning  of  the  signals  given  by  one, 
two,  three  and  four  blasts  of  the  signal  whistle. 

110.  What  changes  do  you  make  in  the  engine  equip- 
ment to  carry  110  pounds  brake  pipe  pressure  instead  of 
70,  for  the  high  speed  brake?     For  the  type  L  triples? 

111.  How    many    pounds    brake    pipe    reduction    in    a 
service   application   will   give    a   fully   applied    high   speed 
brake? 

112.  Is  it  safe  to  use  the  emergency  application  of  the 
high  speed  brake  when  running  less  than  thirty  miles  an 
hour  ?     Why. 

113.  Explain    the    action   of   the   high    speed    reducing 
valve  in  service,  and  in  emergency. 

114.  What  pressures  should  be  in  the  brake  cylinders 
on  the  engine  and  tender  when  the  Straight  Air  brake  is 
fully  applied? 

115.  How  is  this  pressure  regulated? 

116.  Does  long  piston  travel  have  any  effect  in  reduc- 
ing this  pressure? 

117.  What  valve   closes   the   exhaust   from   the   brake 
cylinder   to  the  triple  when   the   Straight   Air   is    applied, 
and  vice  versa?     Explain  its  operation. 

118.  Is   it   good   practice   to   use   the   automatic   while 
the  Straight  Air  is  full  set  on  the  engine  and  tender  brake? 
Why? 

119.  Should  the   Straight  Air  brake  valve  be  left  on 
lap    position   while   operating   the    automatic?      Why? 

120.  How  many  air  pipe  connections  at  the  Distribut- 


268  EXAMINATION    QUESTIONS    . 

ing  valve?     Explain  where  the  air  comes   from  and  goes 
to  at  each  of  these  connections. 

121.  How    many    pipe    connections    at   the    H-5    brake 
valve?     How  many  with   the   H-6?     Where   does   the   air 
come  from  and  go  to  at  each  one? 

122.  Explain   the   effect   of   leaks    from   each   of   these 
pipes  and  tell  what  you  would  do  in  each  case,  if  any  of 
them  break  off.     How   do  you  locate  these  leaks? 

123.  What  is  the  duty  of  the  equalizing  piston  and  its 
slide  valves  in  the  Distributing  valve,  and  what  air  press- 
ures operate  it? 

124.  What   is   the   duty  of   the   application   piston   and 
its  valves  and  what  air  pressures  operate  it? 

125.  Why  does  the  engine  brake  creep  on  when  either 
brake  valve  is  lapped?     How  will  you  locate  this  defect? 

126.  Will  the  engine  brake  stay  applied  if  both  brake 
valves  are  in  running  position?     Why?     Will  it  creep  on 
from  leaks? 

127.  Which    brake    valve    is    used    to    apply   the    auto- 
matic  brake    on   train    and    engine?      Which    brake    valve 
should  be  used  to  operate  the  engine  brake  only? 

128.  What   is   the    difference    in    the   operation    of   the 
engine  brake  by  the   Independent  brake  valve  and  by  the 
Straight  Air  brake  valve? 

129.  Does   the   safety  valve  on   the   Distributing  valve 
control   the  application  chamber  pressure  when  the   Inde- 
pendent brake  valve  is  used?     Or  in  an  automatic  applica- 
tion only?     Any  difference  between  No.  5  and  No.  6  ET? 

130.  What  valve  regulates  the  brake  cylinder  pressure 
in  a  full  application  by  the  Independent  brake  valve? 

131.  Explain  the  operation  of  the  excess  pressure  side 
of  the  duplex  pump  governor.     How  do  you  set  it? 

132.  Is    it   necessary   to    move    the    New    York    brake 
valve  to  positive  lap  position  at  a  brake  pipe  reduction,  or 
should  the  valve  be  allowed  to  move  itself  to  automatic 
lap?     Why? 

133.  Trace   the   course    of   the   brake   pipe    air    in    the 
Westinghouse    quick-action   triple    in    release,    service    and 


EXAMINATION    QUESTIONS  269 

emergency    positions.      Also    do    the    same    for    the    New 
York  quick-action   triple   valve. 

134.  Explain  the. retarded  release  of  the  K  type  triple. 

135.  Explain    the    operation    of    the    Westinghouse    L 
type  triple? 

136.  Explain   the    operation   of   the    New   York   Auto- 
matic Control   brake. 


INDEX 

PAGE 

Air     Pump — 8-inch     24-25-26 

Air   Pump— 954-inch    '..'.26   to   30 

Air    Pump — 1 1-inch    31 

Air    Pump — Cross-Compound     37-38-39 

Air   Pump — New   York  Duplex 192  to  199 

Accelerator    valve — New    York    brake 222 

Air    Signal — Westinghouse     146-157 

Air   Signal— New   York    247   to   250 

Auxiliary    reservoir     22-47-107-136-189 

Automatic   slack   adjuster 174   to    176 

Air  cylinder   lubricator    31 

Automatic  control — New  York  brake 225  to  231 

B-6    feed    valve    62 

B-3  brake  valve — New  York  brake 214  to  219 

Brakes    leaking    off    22-69-125-156-158 

Brakes   creeping   on    129 

Brakes    sticking    127-159-254 

Bursted    hose    ; 143 

Brake    pipe    pressure 22-64 

Breaking   in   two    144 

Brake  leverage    21-177  to  185 

Charging   auxiliaries    6-21-22-136 

Cutting    out    brakes 139-154 

Calculating  air  pressures 186   to   190 

Compensating   valve — Newr    York   brake 241 

Definitions 23 

Distributing    valve — No.     5 78 

Distributing    valve — No.     6 92 

Defective    air    pump 33    to    36-198 

Defective    brake    valve 69-72-125-208 

Defective    brake     128-130-154-158-159 

Defective    governor 42-43 

Defective    triple    valve 17-113    to    115-154-239 

Defective    brake    pipe 133 

Defective  piston  packing    33-35-156 

Defective    air    signal    147-149-157 

Double    heading    98-142 

E.    T.    equipment — No.    5 73    to    81 

E.   T.   equipment — No.    6 84   to    100 

Equalizing  discharge  brake  valve 11-55  to   69 

Equalizing    reservoir    22-56-69-189 

Excess    pressure     52-53 

Emergency    application     14    to    17-109-260 

Equalization 5-18-19-186-188 

Examination    questions    261    to    269 

F-6  brake  valve    .  54   to   56 


PAGE 

F-6    feed    valve    58- 

Full    application     10-23-107 

Governor 41   to    46-200-202 

G-6    feed    valve    60-61 

Graduating    valve     7-106-113-233 

Graduated    application    106-113-233 

H-5  brake  valve    73 

H-6    brake    valve 87 

Handling   trains    on    grades    ..141 

High  speed  brake  163  to  171 

High    pressure    control . 172 

Independent    brake    valve 77-90 

Inspection   of   brake   equipment 21-48-134-135-153 

J   triple   valve — New   York  brake 243 

K  type  triple  valve 116-118-251 

L  type  triple  valve 119  to  124 

Leakage   groove    22-106-137 

Leaks    in    brake    pipe 50-129-158 

Leaks   in   brake   cylinder 22-126-155 

Leaks   in   triple  valve 125-154-259 

Leaks    in    brake    valve 69-72-125-20$ 

Leaky  brake  pipe  check  valve 125 

New   York   brake    valve — 1902   model 251 

Operating    the    equipment 21-251    to    255 

Overcharging   the    brake   pipe 19-127-130 

Plain   triple   valve 5-6-7-108-139-154 

Pressure    retaining    valve 144-152 

Position  of  brake  valve 11-63  to  69-73-75-104-105 

Piston   travel    18-22-138-155 

Pressure    on    brake    piston 18-105-107-138-187-18$ 

Quick  action  triple  valve — Westinghou'se.  .15-18-108  to  114 

Quick    action    triple    valve — New    York 231 

Quick   service  triple  valve    115-1191 

Releasing    brakes 9-131-254-257 

Reducing    valve    62-148-211-249 

Straight  air  brake   101  to  104-20$ 

Slide  valve  feed  valve 60   to  63 

Service    application     .  . .  : 7-23-107-206-233-251 

Safety    valve    85-169-172 

Slack    adjuster    174   to    176 

Testing    for    leaks 49-72-100-125-208-239 

Testing    air    signal 147-157 

Testing    brake    valve '. 69-72-125-208 

Testing    the    brakes 20-125-134-153 

Two-application   stop 19-132 

Trainmen's    questions    150 

Tracing    the    air 255 

Water  raising  system 160  to   162 


MITCHELL'S  MODELS 


Are  a  series  of  cardboard  models  or 
charts,  printed,  colored  and  cut  so  clearly 
as  to  show  the  perfect  and  defective  action 
of  brake  valves,  triple  valves,  governors, 
etc.  The  relation  existing  between  dif- 
ferent parts,  passages  and  pieces  of  the 
apparatus  is  clearly  shown  and  the  function 
of  each  is  explained  in  clear,  simple  Ian- 
gauge  so  that  after  a  little  study  the  course 
of  the  air  can  be  readily  traced. 

No  engineer,  fireman,  trainman,  or  per- 
son desiring  to  qualify  for  air  brake  exami- 
nation can  afford  to  be  without  a  set  of 
Mitchell's  Air-Brake  Models.  They  in- 
sure your  getting  the  necessary  knowledge 
with  least  expenditure  of  time  and  labor. 

For  further  information  write  for  free 
illustrated  circular  of  Mitchell's  Models, 
containing  also  valuable  air-brake  infor- 
mation. 


International  Correspondence  Schools 

Box  1221,  Scranton.  Pennsylvania 


GRAPHITE 


Dixon's  Flake  Graphite  Lubricants 

They  are    the  standard    for    economical,  positive 
and  efficient  lubrication. 

Dixon's  Graphite  Pipe-Joint  Compound 

For  all  threaded  connections,  insuring  a  tight  fit 
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Its  brilliancy  is  unaffected  by  the  elements. 
WRITE  FOR    LITERATURE   ON   THE    ABOVE 

JOSEPH  DIXGN  CRUCIBLE  COMPANY 

JERSEY  CITY,  N.  J. 

THE 


Traveling  Engineers   Association 

At  their  annual  meetings  each  year  since  1893 
have  had  carefully  prepared  Committee  Reports 
on  a  great  number  of  practical  questions  concern- 
ing the  operation  of  the  locomotive  and  its  var- 
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air  brake,  as  well  as  the  proper  handling  of  trains. 
The  Committee  Reports,  together  with  the  discus- 
sion thereon  by  the  members  of  the  Association, 
are  printed  for  distribution  to  others  who  wish  to 
inform  themselves  on  these  important  topics. 
Copies  of  these  Reports  are  on  sale  at  the  office 
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W.  0.  THOMPSON,  Secretary, 

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Chicago  Locomotive  Lubricator 

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3 -Feeds  with  Solid  Sight  Feed  Glasses 


To  Operate 

Open  steam  valve  full  at  boiler.  Open  valve  62  one 
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The  auxiliary  oil  cup  65,  close  pressure  valve  62. 
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1437  Monadnock  Block,  Chicago,  111. 


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Air  Brake 
Inspectors' 
Gauges. 


**  The  above  illustration  represents  a  very  useful  article 
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BRAKEMAN'S 
AIR   BRAKE   AND   SIGNAL    COCK 

For  Controlling  From  Rear  of  Trains  When  Backing 


THE  methods    of    handling  trains  at  terminals  and  passen- 

•^       ger  yards  have  entirely  changed  within  a  few  years  and 

it  is  now  a  universal  practice  that  trains  be  backed  into  the 

station   and  from  there  to  the  yards.     This  makes    it  necessary 

to  have  them  positively  controlled    from    the  rear    end.       It  is 

also  necessary  to  have  a  substi- 
tute for  the  engine  bell,  as  a 
warning  in  passing  into  stations 
and  yards. 

The  cut  shows  a  device  which 
is  designed  to  fulfill  these  re- 
quirements. It  is  a  combined 
plug-cock  and  alarm  whistle  (A) 
attached  by  a  short  length  of 
hose  or  pipe  to  the  train  "pipe" 
of  the  rear  car.  The  whistle  is 
blown  by  pressing  the  button  (B) 
shown  in  the  cut,  which  allows 
air  to  pass  through  the  hollow 
handle  of  the  cock  to  whistle, 
which  is  shown  on  the  end  of 
the  handle,  blowing  the  same 
and  giving  the  necessary  alarm. 
The  air  used  for  this  pur= 
pose,  on  account  of  the 
design  of  the  whistle  valve, 
POSITIVELY  does  not 
affect  the  brake  system. 
By  moving  the  handle  of  the 
cock  in  either  direction  exhaust 
is  made  from  the  train  pipe, 
through  opening  C,  the  brake 
set,  and  consequent  positive  con- 
trol of  the  train  given. 
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especially  during  the  night  or  in  thick  weather,  as  the  train 
by  its  use  is  under  complete  control  from  both  ends. 


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32 


B9A 


Sellers  Non-Lifting  Injector  of  1908 

Has  all  of  the  advantages  and    none    of    the 
disadvantages  of  the  Lifting  Injector 


RE-STARTING 


SELF  ADJUSTING 


When   the  steam  valve   is  opened,  water  is  admitted 
automatically.     When  the  steam  valve  is  closed, 

lazy  cock   closes    automatically. 
WM.  SELLERS  &  CO.,  Incp.  Philadelphia,  Pa. 


UNIVERSITY  OF  CALIFORNIA  LIBRARY 
BERKELEY 

Return  to  desk  from  which  borrowed. 
This  book  is  DUE  on  the  last  date  stamped  below. 


l  6 


gpis  $&  6 


j..e.r 


LD  21-95m-ll,'50(2877sl6)476 


382110 


UNIVERSITY  OF  CALIFORNIA  LIBRARY 


